I agree with Rowan (who has commented above) that it isn't rude if you use the right intonation. However, in formal situations, you shouldn't use it. You should use the correct tag question which applies to the sentence. You signed that document, didn't you? You've met the new C.F.O., haven't you? We are about to begin, aren't we?

I'm relieved to hear it isn't rude. Maybe I shouldn't use it for a while as I don't have a sense what is a rude tone and it sounds challenging... Thank you very much for telling me.

No it is not rude but it used the statement as a question, which is done by many people but is a little odd. English has a question form and it would be normal to use it "Did you sign this document?" is a straight forward question "You did sign this document, right?" is challenging and I wouldn't dream of using it to a boss or a customer. See how just the little addition of "did" makes that sound challenging. Even "you signed this document, right?" is not a good message to send.

No it's not rude. Just make sure you don't say it in a rude tone and you're fine. I personally do it with my bosses and customers all the time.