Should power cords have filters on them?

Everyone say"s you should plug your amps directly into the wall, not a power conditioner so why do they have filters on power cords for amps?I use the Furutech E-TP80 it has no fiters on the amp duplex. I have the Cam 200"s, currently using the Model 11 series II. The Cam"s fuse caps are real close to the IEC connecter,I wonder if Classe knows that!So the power cords with the big round connecters don"t fit.Doesn"t give me many options.Any Advice.Please don"t tell me to sell the Cam"s I do like them!Maybe I just answered my own questions.
I think the ETP80s do have an AC line filter and surge protector. It is the ETP60, which I have, that doesn't have the filter if I remember correctly. I'd suggest you not add filters in either a line conditioner or in the powercord unless you need it such as when you hear static, interferences or sibilance and such in your system.
RatShack or audioquest on the Digital: on captive cords in mid fi. Aftermarket cords in high end digital.
Viggen, Are you saying that filters don"t help lower the noise floor and maybe its the sheilding?
Best world scenario is if your system doesn't need filters, that's all. Use it if you need it.
Fine caps across the hot and neutral can help, without veiling or dynamic limitations. I use good ones in my PoBoxes, for example, but not on PCs per se.
I have tried ferrite clamps and it did help on my preamp. Still think a good power conditioner is better.
Although power accessories, inline or outline, such as power conditioner, surge protector / suppressors, ferrites, choke, parallel filters do help cleaning the power that is fed to your equipment which do help them perform better; a good enough equipment will have a good enough power filteration circuit within their power supply, therefore, minimizing reaction when changing to a very good power cords. In theory, the better equipment it is, the less a good power cord will react it's performance.

For your discussion about whether if a power cord should have a inline device for filteration... My thinking is... a good power cord design should focus on how to prevent interferences instead of how to filter them. Good manufacturers who makes equipments should take care of the filter problem.
Power cord filters are required (by law) in some jusisdictions (Europe, as usual, is ahead of the USA) to prevent equipment from putting noise onto the power lines. This is the opposite to what audiophiles are worried about. Such a "filter" is properly called a "retlif" ("filter" spelled backwards".
Is it possible for you to post without mentioning your own products at every chance you get?
Chris, may I who are you speaking to?
Nevermind. I got it.
Chris, If you don"t know what I have for gear, How can you answer the question? I should say Questions!
If you decide you need filtering, change the IEC connectors on your amps for filtered ones. Get them from an electronics parts place and make sure they are rated for current required by the amp. Then you just need shielded power cords with quality connectors (DIY!) and you're all set.
I mean IEC SOCKETS on the amps, not the cords. Talk to Classe, I think they are a mod-friendly company. They used to make aftermarket cords too.