isn't this the kind of service that will flag a legitimate user behind a VPN as a potential threat because his ip has been used in multiple transactions? Should a user switch off his VPN to do shopping?
If that VPN IP range is known to be used by fraudsters then yes, for good reasons. And if your VPN is affordable and "privacy oriented" there is a very good chance that a bunch of crooks are going to use it.
Professional VPNs are probably fine.