Sister can't leave them with the babysitter anymore as keeps getting bad reports back. Yet she doesn't believe it's true and wants me to have them every Friday over summer. To be honest, I'm not convinced they won't play up for me and it's my one day off a week which I use for housework /catching up with life etc. Don't mind having them here and there but every Friday for 6 weeks is not something I want to do. Aibu ?