Americans...

As a general rule, is 'piss off' as in 'go away' something that people say in the US? Particularly in a semi-professional setting, not meaning it as an insult?

For context, if it helps at all, it's Laura Cadman talking to someone she thinks is a new arrival on Atlantis and saying, "I won't be offended if you tell me to piss off," because she thinks the other person wants to be left alone having not set anything in response to, "is it okay if I sit here?"

If she wouldn't say that, what would be the alternative? Other than 'go away,' but I'm looking for something a bit more informal.

Thank you!