I'm no expert on worms but I have kept them before. If their food/home is not too moist or dry & the temperature is reasonable they are probably ok. Assuming they have a good air supply & nothing too acidic or alkaline or toxic is in their bedding.
Argue for your limitations and they are yours forever.
Sometimes if you add too many scraps for them to eat the bin might get a little too hot because of decomposition and they will crawl up the sides. If they don't all hang out at the top or really escape, they're probably ok. Maybe just ease off on the kitchen scraps a bit and see if they behave differently. Mine sometimes seem to want to escape if the weather gets really damp. This might be their natural time to spread out to new territory and not a sign that anything is really wrong with the bin.