I'll take it a step further and say sampling anything you KNOW has already been used is byting. As a sample producer, it's inevitable. From time to time, you're gonna end up with something already used, but when you set out with the intensions to emulate, IMO(and just my opinion)that's byting. IMO using an already used sample(not talking a flip challenge on FP, I'm talking already made famous loop), or another drum machine/workstation based producer's drums is like finding the exact patches used for a composed from scratch beat and replaying it. Only acception is when an RnB artist turns a famous hip hop loop into an RnB song like Ashanti's "Foolish" or J'Lo's "Jenny From The Block".
Again, just my opinion. I also don't think sampling is stealing, and while I do sample, I won't download cracked software or illegal music. Everyones morals vary.