Ha, I feel this in my soul (and in my empty wallet). I once paid for a "weekend dig" where I spent more time learning to sift dirt than actually touching it, so trust me, you're not alone in this. That 85-person cattle call sounds rough, two hours of trowel time for 500 bucks works out to about $250 an hour, which is more than my dentist charges. The sad truth is a lot of these private outfits are selling a story, not a spot on the crew, and the rope behind the real diggers tells you everything. Your best bet is a local archaeology chapter or a state-run volunteer program, since those are usually free and treat you like a pair of hands instead of a ticket sale.

Is this like how people slowly eat snacks out of the shared office fridge and nobody notices for weeks? Small losses over time are way easier to miss than one big grab. The sign out sheet sounds like the right move, honest guys won't care and the other kind will hate it.