They’re cave-dwelling spiders. They still need a way to find new caves to inhabit. If they’re already settled in your house then they may not survive because you’ve interrupted their lifecycle. But new spiders are wandering in all the time. Those ones may have better luck finding a new house to move into (or coming right back into your house) because they haven’t been established yet.

I made this mistake with a stink bug when it was winter. It was ok with being on the piece of paper I had it on. When I opened the door and the cold air hit it, it backed away towards me. I set it down and it stopped moving. Oops. :(

Big this.