There is a "re-boxing" video showing how to return the phone - they had to provide a special box with a fire proof lining and also rubber gloves because the lining can irritate skin.
I have an LG G3, one of the selling points for me was a removable battery. Manufacturers claim non-removable saves space but if you open a phone with a non-removable battery not much space is saved and the LG G3, for example, is very thin anyway. As far as I'm concerned it just looks like a way to tie the consumer to the manufacturer - promoted, of course, by the ultimate "lock-in" company - Apple.