Relays get stuck all the time, very common in automotive, I'd have to assume a relay inside an amp would be prone to failure eventually too.

 

i don't think ive seen relays in car amps for quite a few years like 10-15
and ususally there on the outputs for prevention of turn on pop and off pop as well as for the protection ciruitry

if your amps turning off and on i would check your power under load and remote on as well that your amps not going into protection because your using a load it dosn't like

 

The "problem" is the remote wire is not hooked up and the amp stays on and will stay on unless I disconnect the power wire from the car.