For both, I say it's best to ask. If you're already using them, post to the game OOC journal and ask if everyone's okay with it. If it's a new character, I'd say ask the mods if that's okay, then once you're accepted, let everyone in the game know in the OOC to make sure they're all okay with it.
There's no great answer on this, because some definitely won't be, but...if you're polite about it, people will be more inclined to let you, particularly if you've already been using it.