this might be more of a bearing than a wheel question, but oh well .
has anyone else had bearings just fall out of the wheel? not like blowing out when it falls apart, just being super loose and going in/out with no effort at all.
it just started happening to me yesterday, i'm thinking it might be a problem with my wheel size as they're getting to <50mm. it was fairly warm (25c) yesterday if that helps.
Definitely a wheel issue, not a bearing issue.
Some wheels do tend to blow out or loosen up too much in the bearing seats, while others are so tight it is an absolute pain to get bearings in or out, even with lube.
If bearings are coming loose, you can either try to keep washers, bearing spacers and everything almost as tight as they can be which should hold your wheels in a little better, or if it is bugging you too much, replace the wheels. Some people have tried to wedge things in there with the bearings, but that often doesn't work as the wheels are urethane (like rubber) and will change shape as pushed, so jamming something else in there will only widen out the bearing seat more.
I had a set that after doing something that put pressure on the wheel, like a smith grind, the bearings would seem to stop spinning, so after each run I had to push the wheel back onto the bearings to make sure it was rolling smoothly again. That got old very quickly, so as I wasn't about to NOT do certain tricks, I swapped the wheels out.
If it is just one wheel and keeps happening in a certain position or as I had, with certain tricks, you could rotate the wheels to see if that helps too, but most likely when something like this happens, there is not a whole lot you can do about it.
Having some crusty old rusted outers on one set of bearings did help with one set of wheels like that, as the rust expanded and stayed in the wheel, but I would not be creating a rusty bearing situation just to have the wheel sit better on the bearings.