Some friend stole my name once when I changed my name for stuffs and giggles. He ran around acting like a loving moron on different servers, including the one I was on. Luckily, he didn't capitalize a letter in the name that pretty much verifies if it's the real me or not. Plus my ID is reeeally low so seeing my name with a high ID means my name was probably hijacked.
Honestly, if friends are going to try and impersonate, they should at least do it correctly.