Agreed. Most electrical lines are rated for 15 amps (I believe). If your outlet looks like a "normal" outlet with two vertical lines and a grounding hole, then it's a 15-amp outlet. It's possible that you could have a 15-amp outlet on a 20-amp breaker line, but as slippery mentioned, that would not be wired correctly - if that was the case, you could overload the outlet before tripping the breaker (or fuse, depending on your house).
I seriously doubt that you'd ever have a problem. I use to have my entire system running through a Belkin that showed the amps and voltage, and I don't remember ever seeing it go above 4 or 5 amps.