We've had similar experiences. Sophie's collar was too loose and it was caught in her mouth like a bridle on a horse and thankfully my husband found her that time. We have a chain link fence and another loose collar somehow got hooked on a piece of the fence. We caught that right away. But on the other hand her collar and tag made it possible for a family a couple of streets away to contact us when she got away. I am happy to report that all the escape routes out of our backyard have been found and blocked
. They are smart, smart little boogers! She is also a little bigger and the smallest collar fits her just right, not too snug but not too loose.