My experience is divided about 50/50 between the "toe clip" era and the "clipless" era. And during that experience, I have seen far more people fall over from failing to unclip than from failing to loosen their toe straps. That may be because many more people ride now than then, or it may be that in the "old days" competency was stressed more than it is now.
Regardless, I have no mercy for people who fall over at stop signs. Properly managed, both clipless and clips-and-straps are perfectly safe. Improperly managed, both can result in injuries.
Short version: if you can be bothered to learn how to use the equipment you have, you will be fine. Otherwise, you're a danger to yourself and everyone around you. And that's really the whole story.