BH bought me a pullup bar for Christmas. It goes over the doorframe. If you are wondering if they ever fall off...
Yes, yes they do. I have two skinned elbows to prove it.
Normally the moment caused by the top bar means horizontal forces are more important than vertical ones. But if you get overenthusiastic, you can knock the stupid thing off the doorframe and fall in a heap in your hall.
Chalk this one up to experience: slow and controlled movements.