Am I Getting Hacked/Have I Been Hacked?

Something similar happened to me the other day, someone's character appeared as my main character. I checked under 'My Characters' or whatever its called and my I/L Arch Mage was still listed as my main. A few hours later, it reverted back to the way it was before. It's likely a glitch, I wouldn't be worried.

Thanks for the reassurance, I'm still patching, and will check anyway. Didn't think glitches would be like this.