I'd also like to know.

I'd also like to ask people not to block this way. It creates LOTS of false positives. There's much better ways to handle bots and this tactic seems particularly dumb for Reddit given they want users from places like China or elsewhere where a VPN might be required. Not to mention people using public WiFi. It's not like VPNs are uncommon these days.

If you must ban IPa then do so with a timeout and easing function. So that each hit results in a longer ban time. Bots want to move fast so even a few seconds ban time will make them switch IPs while not impacting most users (who will refresh)