If this is the kind of box you're doing, I don't glue the bottom in.
It would be the same if you're making a box,putting in a top and a bottom, then cutting the top off, again I don't glue it in.
The corners hold it together, loose panel just barely loose. I haven't been bit in the backside doing it like this. Maybe I'm lucky.

I'm probly going to let you down but, I swear I won't keep you down. John Hiatt