I can agree with that. I do not worry about a raccoon even getting to my pop door, though. It is on the inside of my run that is very raccoon proof. Actually, it is predator proof period. I guess the door is just a redundant protection.The problem that I see with any of the doors that use a string to raise the door and gravity to lower it is that a smart raccoon could easily figure out how to raise the door manually. Less secure than the doors operated with a screw drive mechanism.
I could of just built one, but for what one cost not much of a reason to unless you just wanted to.
What particular brand and model has the screw drive mechanism?