Ya the thing about sparring is the other guy may be recovering from a workout, or on a light, rest day. You CANNOT be 100% even on fight day,there is no way you are going to be completely on for each guy you spar with. Also there's the respect to training partners u don't know. The point is Rockhold didn't spend months preparing for bisping. I hate dude in gyms that try to go reallly hard, hurt everyone , get injured, never improve technique and never learn anything new. That seems to be the type of guy "oh I tapped so and so".
I respect Bisping as a fighter but that whole " beat this guy" in sparring is kind of a chicken hawk move.