[poincaredisk]

The downside is that you ban a whole ISP because of a single user misbehaving.

Personally I sometimes do a quick request to /wp-admin to check if a site is WordPress, so I guess that has a nonzero chance of affecting me. And when I mirror a website I almost always ignore robots.txt (I'm not a robot and I do it for myself). And when I randomly open robots.txt and see a weird url I often visit it. And these are just my quirks. Not a problem for a fun website, but please don't ban a whole IP - or even whole ISP - because of this.

[b112]

Well you make a point, I use ipset in many circumstances, which has an expire option.

So that is a balance between a bad actor and even "stop it" blocks, and auto expire means transitory denial.