Our good friends have 2 DDs age 3 and 5, we have 2 DS's of 2 and 5. We look after each others kids from time to time, but both acknowledge that it is pretty hard work to look after all four together and so only ask the other one in emergencies/ if we are really stuck. Usually if we see each other for playdates etc, the adults (usually me adn the other mum) will stick around.
The friends went away for a two days without the kids and their grandmother came to stay in their house to look after the girls. They gave the grandmother our number as an emergency contact. Day 1, after she picks the girls up from preschool the grandmother calls me. I got very worried seeing her number pop up as I assumed it was an emergency. She asked me if she could bring the girls over for a playdate. I said yes assuming she would stay around. But when she turned up it was clear she wanted to drop off the girls with me and go out for the afternoon by herself. There was no emergency, she just obviously couldn't be bothered to look after them. But it was hard to say no because when they arrived the kids were excited to see each other and it was hard to disappoint them. Having all four all afternoon was hard work and meant I couldn't take my two out for the afternoon as I didn't have enough car seats. AIBU to be annoyed? Or am I being precious?