In my stackable bin, I have always had worms up the sides and even under the lid, but the vast majority seem happy to stay down.

In totes (reletively new to totes myself), they do seem to stay down rather well in the newer ones, but less so in the older ones.

Conclusion ; I reckon it's fairly normal. If the bin isn't too moist (ie running water), and doesn't stink (ie gone sour), then all should be good.

If your bin has been going for quite some time and the worms are just beginning to crawl out, I would say there's something wrong inside your bin and we need more information to help.

Other than that, I think it's normal for a worm or two to crawl around and explore their surroundings.

I always get a few escapees - mostly they end up in the drainage fluid on the bottom.

Here's another idea. I'll assume you're using a properly designed bin that has drainage in the bottom and some air flow.

If a large percentage of the population thinks it's time to leave, there might be a reason. It can be hard to figure out since we can't think like a worm (unless it's obvious, like everyone is drowning), so another way to tackle the problem is to make the environment less homogenous so they have options: shredded cardboard in that corner, rotting banana in the other corner, dry over there, little wetter over here, shovel of soil/compost down there, like that. With an inch or two of shredded paper over the top of everything.

Hang in there - it can take a while to get a new bin stabilized.