I use a large perspex cover to keep my Platine Verdier away from my childrens and our cats hands/paws.
Can you block it off with furniture? Or, a toddler fence? How about closing the door and making the room off-limits? You could cover it with a blanket so she can't see it -- out of sight is out of mind? Or, you could distract her with something else in another room. I suppose it would be expecting too much to ask her parents to keep her away.
If all else fails, I would move the turntable and suffer the inconvenience of repositioning it back afterwards. Perhaps it could be easily elevated on a portable support. Good luck.
I have the same problem and solved it by placing a strap or belt around the plinth and cover which I remove when my grandchildren are gone. Works just fine.
Of course, that didn't stop my grandson from tweaking the treble on my C2200. I went through 3 sets of tubes 'cause I didn't like the sound before I discovered that the problem was the treble knob that was cranked to the Max. After living without bass and treble controls for 15 years I completely forgot about it. As my son would say... "Well, Duh!"
OK. OK.. So, Gramps is a slooow learner...
Unless you plan to CONSTANTLY monitor, you should move the table to a higher spot, out of reach. I've seen firsthand the damage a child can do to cartridge, tonearm, and valuable vinyl. Not pretty!
Why put yourself through the stress, and the parents through the possible guilt?
Go high, preferably with a wall shelf.
I realize all kids are different, but I was able to teach my son that some areas are a "no."
The "no" areas included things under the kitchen sink (we did not lock the doors), electrical sockets (no hairpins please :^) and my turntable.
By the time he was walking, talking and had a reasonable understanding of things, I showed him how the turntable worked and he would cue up music while I sat in the hot seat. My TT at that time was a Versa Dynamics linear tracker with Benz Ruby cartridge.
I have a Polaroid of him standing beside my expensive gear with a grin from ear to ear. He was laughing out loud when the music burst into the room.
No, he never broke my stylus or TT, he left that for me to do while I was cleaning the body of the cartridge with a Q Tip.
I should have let him clean the stylus.
I took a different approach, which has worked (so far).
We have a 22 month old, and I bought him an old Kenwood direct drive that he can play with all he wants (not plugged in), it's just sitting on the floor in his play space and he has his own little library of records that he can chew, dance on, or spin - it's up to him. He gets excited when I bring him a new record too! Once he's old enough I'll see if the table will still work so he can really use it, but for now, it definitely keeps the heat off mine.
A very none politically correct idea is
It may be your grandchild but it is your offspring's child, hence if they wish to visit and have you be relaxed and enjoy it, it is their responsibility to either pay attention to their child or not stay to long.
A visit is meant to be pleasant not unnerving
Having no grandchildren yet I can say this, when I do I may regret it.
Fortunately my kids are old enough that they know that to touch my stereo guarantees a serious readjustment of their VTF (especially when they later try to sit).
If I had a baby or toddler to worry about, I'd put something big and/or heavy on top of a tablecloth on top of the tt. Out of sight, out of mind, out of harm's way.
Uru, kudos for bucking the pc trend. In my experience however, even the best-behaved kids are prone to accidents or unprecedented dares. With a deep-four-figure cartridge that no child would recognize as pricey and frangible, for my own peace of mind I'd opt for removing (disguising) the temptation.
Save the cattle prods for cable burn-in, amigos!!
I sounds like you already have plenty of good advice, but I'll weigh in anyway. I subscribe first to Albert Porter's approach. In my case, my audio was in a room that was off limits,and my kids surprisingly behaved.
On the other hand, I'm a little surprised to hear you say you prefer your table low. I mount mine at chest height. I really don't like bending over to position records. Were it me, I'd move it to a higher, sturdy location - possibly wall mounted as Dave suggests.
I too used the common sense rules that both Albert Porter and Bdgregory have alluded to. Teach your children well, and they will respect your property. My little girl is seven, and has never gotten into, nor played around with any of my stereo equipment, which I will point out is in our living room, so she does have access to it. (However, while she was a toddler, I did have a small indoor "fence" around my equipment until she was old enough to understand what NO meant. So for about one year, from age 2 to 3, she was physically separated from my equipment.)
Unlike Albert though, I left the breaking of my cartridge to my friend's children (ages 8 & 10) when we had a BBQ at my house. (They had never seen a turntable before, and so strummed the cantilever, of my Benz Micro Glider II, like a guitar string). Ouch! No more exposed cantilevers for me!
(Luckily, my friend came through and kicked in some money toward a new cartridge, which was cool. I now try to get cartridges without exposed cantilevers, like Shelters and Koetsus, which I prefer anyway.)
My two cents worth!
Have something at your place that the girl loves more than life itself...Hello Kitty stuff seems to be high on the must-have list these days. Then give it to the child to play with only (1) while at your house and (2) only if she keeps away from the turntable.
We use the technique of "putting things on vacation" with our kids (4 and 6) and if the object that is threatened is high status, the threat works wonders. (E.g., if you don't practice piano right now, your "weird and wild creature cards" (the boy); your "hello kitty treehouse" (the girl) will go on vacation.) And of course, follow through is everything.
Perhaps mark a circle on the floor 4 feet away from the tt with tape or something and if the kid passes the barrier, the coveted item goes on vacation. That way you don't have to wait until it's too late.
For the time being, I've opted to go with a variation on the acrylic cover with the out-of-sight-out-of-mind principle thrown in for good measure -- a hastily fabricated cover of 1" X 8" frame topped with a piece of quarter inch plywood and a little bit cut out of the back for the connecting wires to run. Cheap enough to just pick up and toss into the garage when our granddaughter's not visiting and hopefully ugly enough to deter the fascinations of pre-kindergartners when it's in service protecting the turntable. If this doesn't work, I'll probably opt for a Target wall mount setup but have really wanted to keep the current location if at all possible due to a combination of optimum sonics and optimum visual harmony in the room
If all this fails, I suppose I'll call Dr. Laura and face the inevitable verbal lashing....lol...