Same at any motor sports events.
TET the same low level happens at most sporting events, F1 GP at Albert Park, the bikes at 'The Island', etc and if you have at look at the AIP Supps prior to an event they often specify block levels for the camera ship, scenics and then the micro-wave up-link above that.
Then there is the get out of the way times when various MIL A/C do their recruiting routine.
The camera ship will often be at about 500' agl and trying to fly within the crowd/course.