PM people in dungeon

[Riepah]

But that could cause a lot of confusion if you try using the /tell to talk to a party member in the dungeon with you. (And I'm sure plenty of people would try to use it that way.) If someone on your native server happens to have the same name, they'd get the message you'd intended to go to someone else. It would just be too error-prone to be a good idea.

The off chance that somebody would try to whisper somebody from an entirely different server in the same duty as themselves, who just so happens to have the same name as some other person on the server is enough for you to suggest that it's a good thing that we're unable to whisper during duty...?

[Niwashi]

The off chance that somebody would try to whisper somebody from an entirely different server in the same duty as themselves, who just so happens to have the same name as some other person on the server ...

There are plenty of popular names that appear across multiple servers. I don't think that "off chance" would be unlikely at all. It could happen a lot.