AITA for asking my sister to pay $340 after she brought her daughter on a pre-paid lake house trip without telling anyone
This is going to sound petty but I need an outside opinion.
Back in May I organized a long weekend at a lake house for four of us, me, my sister (37F), and two of our mutual friends. We split the rental cost evenly before anyone booked anything. $340 each, transferred to me upfront. I was clear about the headcount because the house had exactly four beds.
My sister showed up with her daughter (16F). She did not mention this to me or to either of our friends beforehand. She told me at the door that she assumed it would be fine since her daughter "doesn't take up much space" and would sleep in the bed with her.
The daughter ended up on the pullout couch in the main living area because sharing a bed didn't work out. Our friend who'd planned to use the evenings for work had nowhere to sit. The daughter ate most of the shared groceries we'd all stocked together ahead of time. My sister doesn't drive, so every time we went anywhere we were on the daughter's schedule too.
After the trip I sent my sister a Venmo request for $340 same as everyone else paid. I said it was a late addition fee since her daughter was a fifth person in a four-person rental. She called me and said I was treating her teenage daughter like a hotel surcharge, and that it's embarrassing to charge family for this.
I told her the four of us each paid $340 and her daughter was a fifth person who slept in the house, ate the food, and used the car. She's now telling our mom I'm "obsessed with money."