[ghxst]

That's a fair point, probably the best approach would be to do a client side challenge where the server side challenge fails but at that point it's no longer as simple of a setup. Toggling a VPN is definitely annoying but a captcha or something like POW do come with an impact to user experience as well and in my experience are easier (and cheaper) to deal with for bots, a good quality residential proxy where you pay per GB quickly becomes a lot more expensive than a captcha solver service or the compute for a POW challenge.

[dmantis]

Yes, but you can use captcha/POW challenges based on IP reputation, which leaves usual users intact. I don't mind captchas too much, that's my choice to use the VPN.

What I mean is that it's better to give VPN users the choice to solve captchas instead of being banned completely.