Sounds like the BIA is hunting for drug charges($). People know about the elephant in the room: there's going to be a lot of drugs at Burning Man. For police, it's like a fisherman watching a fish migration happen in front of them.
The error here is assuming that BIA cares at all about Burning Man, which it likely does not. Burning Man is simply a high-traffic road where traffic stops cannot be avoided, permitting them to search every vehicle without contest.<p>This reeks of a deal where BIA offered a bribe in exchange for permission to perform traffic stops and searches from the local police, and they’re confident they can execute a full set of searches on a captive audience before a judge lays out an order requiring the bribe (and accompanying contract) to be divulged.