Sounds like a good way to get stopped by the police.
"Hey Charlie? What are all those weirdos with GPS units doing in the park over there? Oh look, they found something! Probably a drug drop! Better get this on video - and radio for some backup. I wanna find out what these jokers are up to."
Actually, it reminds me a little of a game we used to play in college where the goal was to hunt down the secretive and elusive Paranoids Anonymous
organization. Clues would be given during the month that would start you on a trail. The trail led to a sequence of clues. If you completed the trail and figured out all the puzzles successfully, you'd eventually figure out where Paranoids Anonymous
was meeting that month. (The 'meeting' was actually a really good private party.) If you could find the meeting place (which could be anywhere in RI, MA or NH) - you automatically became a member.
Kinda like the much later 'rave' parties, except ours weren't so heavy on sex, drugs or general weirdness.