I don't disagree with you completely,
@Ollie , and especially with respect to the S5 since I've had NO exposure to that phone at all. Just curious, with regard to the S5 and by the word "certified", do you mean certified water resistant or something other?
Truth is most phones with removable backs/batteries seem to be free of problems in that regard, but I have seen my fair share of phones dropped with removable backs where what has often happened is that at the point of impact the back flies off, the battery is ejected, and the phone goes flying in another direction. In fact, my OGD and D2 have both been dropped by my son on several occasions, fortunately the screen never cracked - however the cover and battery has gone flying on several occasions. I've seen the same thing happen with an S4. I've never seen the back or battery come off of a phone dropped which doesn't have a removeable back.
I have also been in threads in the past where the phones would cut off or go black while on a call, and it seemed to be related to a loose battery. I am sure I could find an example of that if I searched.
These may be rare examples, but they happened.
Another thing that may be a contributing factor regarding removable backs/batteries is that the tabs that hold them on (depending on the design), could potentially begin to round off over time and eventually the back may become more succeptible to falling off, and with it the battery.
