Had blood raiders do that to my settlement once, had to hire mercs to clear them out but I was originally able to walk past them. Granted putting a ton of them into peelers later on and killing them on sight made my relations drop to -100 so now if they did something like that it would be hell.

"30+ bandits streamed past me only to stand gormless in a shed, throwing a tantrum whenever someone infringed upon their cosy cabin." lmao I wouldn't doubt shrieking bandits having that as a feature