I don't wait if it's DH, or even one of my own kids. Mostly because I know that if there was a problem, they would be calling me right away and I could just go back. I do usually wait if we are dropping off one of my kids' friends. I guess I feel more responsible for them, and less sure that they would call us right away if they had trouble. Personally, I never expect anyone to wait if they drop me off. I consider myself to be quite capable of dealing with any issue that comes up on my own, and hate to feel like an extra burden.