They are Division 1 athletes! They didn't get to this level by happenstance. You can't TELL me they can turn off their competitive nature in front of millions of viewers and NFL scouts. Once that whistle is blown, they aren't thinking about anything but competing. I wrestled and boxed in high school, and did some MMA afterwards. I'll admit; sometimes, before a match, I didn't want to be there. But, when that whistle blew, there was nothing I could do to keep that switch from flipping. There was no way I was going to get embarrassed in front of a crowd! And, that's how everybody I competed with was, too. There's no way you can convince me that these players don't feel the same way - especially on a MUCH larger stage.
And, I guarantee that the coaches responsible for scouting and creating a gameplan know that their jobs and reputations are always on the line.