That may be a result of the staffing available to me, but it makes more sense to me to bang around a release for a few days, and then say, "Well, no show-stoppers in the last few days -- let's release!"
I've also worked in very small teams where we had no dedicated QA. Even then, I have a severe distrust of the kind of ad hoc testing you get from banging around a release for a few days to see if any of the bugs in the product somehow appear. If anyone finds a bug, I want to find it, understand it, fix it for good, and then ensure that it and bugs like it can never appear again. I don't think you get that without serious testing and root cause analysis, and I know you don't get that often (if ever) if QA is a separate entity from development.