Collect everyone's share upfront, before you reserve the site or buy the passes, into one place the whole group can see. One person holds it, and every dollar in and out is on the record.
Group camping and festival trips look cheap until you add it up: the campsite reservation, the festival passes, the coolers of food, the gas for three cars. Someone always fronts the big pieces and then chases everyone through the group chat while trying to also plan the trip.
Half the cost of a camping or festival weekend is the running stuff: the group grocery haul, the ice runs, the gas splits, the last-minute tent someone forgot. Instead of one person fronting each one, collect a little extra into the table at the start as a shared kitty.
Then whoever pays for a group thing requests that amount from the table, the organizer approves it, and everyone watches it come out. Nobody keeps a tally in her head, and the money left at the end is on the record to send back evenly. (A camping trip that's really a long drive first? See splitting road trip costs.)
The organizer holds the money the way she always did, only now everyone sees every dollar. It goes through Stripe to the organizer; TableCash never holds it and is just the record.