That's the strength of the signal but doesn't mean anything about the ability to connect to any particular service.
Besides the need to login/register public WiFi services often block a bunch of things other than basic web browsing so not...
Yeah this has to be damage caused by crushing the bag while stored or such.
Stress cracks would be a fine line but it wouldn't separate that far, there had to be some force applied.
I find it highly doubtful that this sort of major cracking can happen through normal wear and tear and exposure to air and light. I would guess that UAV has, at some point or other, perhaps been rammed into a bag too hard, or been put in a...