who are all these people registering?

[kathisterima]

If said IP's that were bought are freshly obtained and rarely used or never used then they should be clean and not indexed for any activities on whatever database you are referring to 

Reason why other proxies can be detected. The tunnels they used are indexed no? 

IIRC most people who actually have a use case that requires really strict OPSEC they would buy fresh virgin proxies that never have never been used

OFC I'm digging too deep into this, I doubt these users are going that far

A dedicated IP address is something different. You can buy a dedicated VPN IP as well. The thing is shared use provides an extra layer of protection and anonymity, which is the point of hiding your IP address.