Here is Anet's policy regarding third party programs, directly sourced from their official website:
->In general, our policy is as follows:
We do not permit the use of any program that gives one player an unintended, unnatural, or unfair advantage over another player. This includes programs that alter game balance in favor of one player over another, automate actions within the game, promote unattended gameplay, or have an adverse effect on other players.
The best way for you to assess whether a specific third-party program could have any impact on another player is to ask:
"Does this program allow someone to play faster, better, longer, or more accurately than someone who doesn't use the program?"
"Does this program allow someone to 'play' when he/she is not at the computer?"
"Does this program allow the user to gain unnatural or undeserved rewards?"
If the answer to any of these questions is "yes" or even "maybe," then we strongly recommend that you do not use the program. Doing so not only raises the risk that your Guild Wars or Guild Wars 2 account may be accessed by a malicious third party, but it can lead to the suspension or termination of your account for violating the Guild Wars 2 Rules of Conduct.
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-Using Discord (or any voice communication program) does in fact give one player an unintended, unnatural, and unfair advantage over another player who is not using voice comms (third party program).
-Using Discord does in fact allow someone to play faster, or more accurately than someone who doesn't use the program.
-Using Discord does allow the user to gain unnatural or undeserved rewards.
Because of this, Discord voice communication in any competitive game mode is considered a ban worthy offense.
Correct?