When it comes to other parents, I don't *insist* on anything. (I assume if they have my child, they'll keep him safe, but that's about it.)
As a courtesy to other parents, I tend to ask them first, and it seems other parents in our area do the same. There may be reasons why their child(ren) can't go with us, and it's easier for me to check with them than it is to go back and forth through the child. Most of these parents are my close friends, anyway, so it just tends to work out that way.
Also, with us, all of the kids are still young and most of them have schedules that are already so booked up with sports, music, dance, scouts, religious ed., etc., that there is not a lot of free time, so I usually get the best information about whether someone is really available to go with us when I ask the parent.
I wouldn't be bothered if another mom asked me to check with her first. I guess I'd figure she must have some reason for her request, and I wouldn't dismiss the child or X him from our list of friends because of this. Seems kind of unfair to the child.
As kids get older, they do tend to take on more of the responsibility for their social schedules, but while they still need to be driven everywhere and while they have numerous other things on their schedules (that they don't always remember), I don't see where it hurts to check with the parent.
Also, I've seen where kids get so excited about something and start asking all their friends to join in before checking with their parents to see if this is okay. It would be kind of awkward to call another parent and ask if they really meant for my child to join them at ______, especially if I didn't know the parent as well. These parents might be surprised to find out that their child has invited 5 additional kids to go with the family when the parent was thinking only one additional friend would be accompanying them.
Anyway, that's just how it's done in our circle for things outside of the simple going outside to play in the neighborhood or park play dates.
J. F.