Honestly it's the type of event that I think is more enjoyable and useful to watch at home on TV or on the computer, so I wouldn't feel too bad. You won't miss anything, you can pause and rewind, etc. You have a better vantage point for the agility/movement drills, the gauntlet, etc. (Which are pretty much the only drills that I think are necessary to actually watch to get a feel for a player amongst his peers in a controlled environment--the track events, the numbers are the important part and don't really need to be watched).
If you're there in person, you're basically at a track and field event filled with amateurs, seems like it would be boring. Unless you have a chance to interact with players/coaches and that's up your alley, I have no idea, I assume they keep the fans in attendance on the other side of the fence, so to speak.
Seeing these freakish athletes putting up crazy measurables from 20 feet away could be cool, maybe I'm wrong. Just seems like for the stuff we're interested in as football fans and fantasy/dynasty owners, being there would just prevent you from having a great vantage point to see what you really want to see.