Is in the process of reversing them.
Arenanet apologized today for erroneous bans, promising that the company is in the process of reversing said punishment. It appears Guild Wars 2‘s anti-cheat program flagged GeForce Now as a bad program used by bad people, and banned a number of accounts caught using it.
GeForce Now is the cloud service run by Nvidia. It allows gamers to access their games over cloud to play owned titles on devices that otherwise could not play those games.
We have discovered that some players who use the GeForce Now service had their accounts suspended unintentionally. We are in the process of reversing these account suspensions and we’re investigating the cause to prevent this issue from occurring again. If you are still experiencing issues with logging into your account, please reach out to our Customer Support team at https://help.guildwars2.com/. We apologize for the error and thank you for your patience.
Source: Guild Wars 2