I'm very much 'in charge' when it comes to arranging and booking trips etc. I planned a holiday with this friend, let's call her Susan for arguments sake.
I gave her the price for the flight, the hotel and activity cost while we're there. Susan agreed. The following day she walked out of her job and contacted me to say she couldn't pay immediately for the trip. I was annoyed but agreed to her repaying me in installments.
She messaged me last month to point out something else that we should do on the trip and I agreed it looked great and booked it (it was on offer) and said 'so you owe me £40 for your half'. She hasn't acknowledged it or sent me the money yet.
The flight carrier's luggage allowance has changed since we booked and I need to go on and add luggage to the booking. AIBU if I just add on luggage for myself and send Susan the log in details to do her own? I sense if I do this she won't actually manage to organise it herself and we're going to have chaos at the airport. But I'm not her mother!