Not familiar with GFI disconnects. I'd guess that like most electrical boxes, there are knockouts top, bottom, sides and back.
So far my 48+ month old GFI breaker hasn't been prone to false tripping- it gets tested every time I change water, which is every 90 days or so.
I suppose it's possible that they can wear out- anything mechanical can and eventually will, but I've not heard it as widesread problem.
Sounds like a bit of marketing hype to me.