Ball stops for underfloor speaker cables

Hi. I'm running speaker cable through an insulated crawlspace, with enough slack so that the speakers can be positioned for listening or tucked away to keep the room tidy. Naturally, I terminate the cable at the speakers rather than at a wallplate because fewer connections are better, I'm told.

One of these days, because of children or guests, the cables are almost certain to get damaged where they enter or exit the floorboards, and I'll be out both expense and hassle fo re-run them.

I think a "ball stop" (similar to what you might find on the end of a retractable vacuum/sweeper cord, or on a retractable pneumatic line in a commercial garage) will ameliorate this risk. Is anyone using them? If so, have you identified a less-unsightly version or manufacture?