IP, shmy pi...
I have booked a number of tickets on other people + manage all my fam accounts from my PC, and have never gotten an audit. Looks like there is something else in the story that might be missing, i.e. trail to an ebay auction, or craigslist posting?? op needs to give more details.

If what he says is true then I'd small claims to the max, and i guarantee you he will win.