alt Hacker News> you only need to detect a VPN connection once to prove violation
But an IP address is not a person (legally in the US at least), and many IPv4 addresses get re-used fairly often. My home 5G internet changes IP every single day, and it's a constant struggle because other users often get my IP blocked for things I didn't do. I cannot even visit etsy.com for example. Just for fun I even checked 4chan and the IP was banned for CP, months before I ever had this particular IP (because I'm paranoid and track all that stuff).
> But an IP address is not a person (legally in the US at least)
That's a completely different matter (and still probably reasonable suspicion for a search, anyway). If an account/service ID evidently uses a service through a VPN there is no uncertainty of ToS violation. Of course someone could have hacked your account and used a VPN, it doesn't ultimately prove you did it, but nevertheless the account can be flagged/blocked correctly for VPN usage.
> many IPv4 addresses get re-used fairly often
The VPN's servers won't be using changing, "random" IPs. That's something ISPs do when assigning residential IPs. VPNs with residential IPs are not common. (I am not sure those VPNs are even really legal offerings.)
If your ISP uses NAT for its subnet space, you could argue it's technically similar to a VPN. However, same as with VPN exit scraping/discovery, those IP spaces can be determined and processed accordingly. I am also sure those ISP subnets for residential IPs are actually publicly defined and known. Eg. the Vodafon IP may get temporarily flagged for acute suspicious behavior, but won't get your account flagged for VPN violation, or even blocked permanently, since it's known to be the subnet of a mobile ISP, which uses NAT.
Additionally, I presume e.g. SoundCloud prohibits anonymizing VPNs, not everything that's technically a VPN or similar.