[Josh Fox]

There are a couple difference I can think of off the top of my head between drive team members and MCs running and jumping around the field.

First, when MCs are running around the field, there are generally no other people on it carrying very heavy robots at risk for collision, which can't be said for when drive team members are setting things up. It's a relatively more controlled environment.

Second, and I'd argue this is probably the "real" reason, is that there are much greater concerns about students injuring themselves as opposed to adult volunteers, and people feel more comfortable letting adults assume risk for themselves.

While I agree it kind of sucks that a very momentary lapse in judgement (stepping over the field border/defenses) that probably isn't leading to that much of an increased risk can be of grave consequence to your team, there's also a great deal of emphasis from all announcers and field crew that those actions aren't acceptable.