Is it alright to ask to take the next available stall (when there's a line) because your young child needs to use the bathroom, or risk having that accident? What do you think?
Personally, whenever I'm in line for a public restroom, as long as I don't have my own potty emergency with one of my little ones, I always let very young children, pregnant women, and elderly people go ahead of me. (I'm also the type that chooses a further back parking spot when I'm shopping alone or with my older kids; I would rather leave close spots for the moms with young children or elderly folks who need a closer spot since my legs work just fine) I just feel it's polite, and in general, I find good gestures tend to go full circle.
As to the original question, I have not been to DL since I was 6, but I can answer in the general sense. I have zero problem with a child under the age of 5 being brought into line later. Yes, children do need to learn to stand in line, but sometimes a three year old just has a mind of their own! I would get annoyed if it was a handful of teenagers that just didn't feel like standing in line though.