The example was not meant to be taken literally. Think of something you don't want your child to do, whether with you or at all. Think back to when she was 6, if there is nothing you don't mind her doing now.Again, that wouldn't arise with me, because I'm not concerned about her being up too late - going to church sleepy never killed anyone. As for not doing well on rides, I would leave it up to DD - if she wanted to go anyway, fine. If not, I'd volunteer to go get her so that their plans weren't ruined.
The point is that, if someone goes through the trouble of asking or informing a parent about a sudden change of plans with their child, to something the parent doesn't approve of, it is a rude and selfish overreaction to respond "if you don't trust me to do this with your child, you must not trust me to do anything with her, so just come get her now." If they don't tell me and I find out about it later, I'm not going to be upset. It's done. But if they give me the chance to voice my opinion, I expect them to respect it.
That said, to be honest, in this type of situation I'd politely offer to pick my dd up too, although I don't know a single person who would let me. My friends and family would immediately drop whatever ideas I disagreed with, so that they could spend time with her.
If you have no friends or family with whom you have any difference of opinion regarding the safety of any activity or any aspect of parenting, more power to you. I'm amazed, really, because I don't know a single person who shares my opinion on every single thing. We still trust each other and don't take it personally when one asks the other not to put our kids into a certain situation.
OP, I think you sound like a great sister, too. I'm sure your sister appreciates your respecting her wishes. This is the 6yo's first time away from mom. I'm sure that after this trip goes well and the child gets a little older, she'll have an easier time with it in the future.
