Last night I tried playing GW2 through Geforce Now streaming on an alt account. Did my dailies and logged. About an hour later I went to log back into that account, without GeForce Now, and was met with the error message "The code you entered is invalid." I've since contacted support and was told that my account was "caught in our regular account security review," but that it was rechecked and was now unlocked. That was about 8 hours ago, and I'm still unable to log into that account. I'm confident this will be resolved, but there's definitely a bigger issue here.
The support rep did mention that playing via a VPN/proxy is not condoned/supported, and has been associated with account fraud. This is a fully understandable position when dealing with normal VPN service, of which there are countless. But my account was flagged using nVidia's GeForce Now, a service that Arenanet has seemingly opted in to participate in. GW2 was part of the service at its launch, but disappeared shortly with many other games and nVidia moved to only have games who's devs/publishers chose to be on the platform. Despite that, we seem to still have support locking accounts that log in via nVidia's servers. They really need to be double checking before locking/banning when the login is coming through an IP operated by a gaming service Anet already clearly has some degree of official support for.