@pollysmps: Soul Memory is about the only reason I don't want to do any PvP in DS2. They either need to remove it or rethink it. For that reason alone, every time I get invaded which hasn't happened too much, I just stand there and let them kill me.
I am also pretty sure many PvP people use the infinite stamina or the infinite spells. I see them swinging till there's no tomorrow only to do 300+ rolls and then spam spells that I know for a fact the number of times they can use without using herbs to replenish them.
That said, I have no problems with people using trainers in for the single player aspect, or to train on enemies but is you do either do it offline or if you and your buddy using it to train for PvP then at least make sure to do it in a spot that's not full of invaders.