The point many of you don't seem to be getting is that it's not about trust for many of us. It's about being able to relax on your trip, knowing that your kids are in familiar territory.
I let my kids go places. My family could take them on an overnight trip to a waterpark, no problem. However, while they are gone - I will be HOME, where they can find me easily if needed. They will have a good time, knowing that I am home waiting for their return. I would be spending quite a bit of my time thinking about them, knowing what a good time they are having.
However, if I leave my kids, it's a rare treat. A time when I want to relax and forget about parenting. The times I've left them they've been at our home with grandma and grandpa or at g &g's house. I can visualize their routines and spend little to no time at all thinking about what they are up to.
If my sister or parents decided to have a big adventure during the one weekend every five years I might decide to get away, I'd be the one who would be

. They have access to my kids almost any other weekend they would want them and they choose THAT weekend to have a big adventure?
Heck, my kids are 11 and 14 and I would STILL enjoy myself more on a getaway if I thought they were home in familiar territory doing familiar things. If they were on their own getaway, I'd be wondering what they were doing. Selfish? Yes, but isn't that the point of getting away without the kids? Spending time on yourself for a change and not having to worry about the kids!