You must have a lenient workplace if they allow you to fly RC aircraft at lunchtime. It seems a tad unprofessional to me, but, I suppose it depends on where you work.
As for the rest of it, you have a choice: Comply, or don't. If you do not comply, there might be consequences. Those consequences might include termination. It's up to you whether walking across part of the parking lot or flying an RC copter is worth the risk or not.
Oh, and the guards may not be "tripping" they may have been given marching orders that include enforcing some of these arguably "petty" rules.

