Some people are smart to clean things up... but I don't think that most are. Many still don't even know how the privacy settings work (it's how issues like this
*I do not condone this bartender's comments, actions, reactions or behaviour in any way shape or form. Her attitude is despicable and disgusting and indicative of someone who is not fit to work near people.
Cases like the above are surprisingly common with people getting fired for things they do/say in an increasingly online world.
Though I do agree that if the company finds nothing it may prompt them to try digging harder.
As far as I know, nothing is ever truly deleted. They store everything posted on it in some fashion. (Possibly for legal proof if needed. Like if someone posted they stole x, y and z. Police get the confession from the site and use it as evidence.)
Unfortunately everything we do in our past can come back to bite us, no matter how old we were when we made that decision. And we have to live with the consequences of our actions/inactions. I agree it's not always right (there are some cases in which I do think past actions should always be considered) and many people aren't forgiving and don't want to let the past go. But this issue is only made worse when they can see thoughts/decisions from years ago more easily now with the power of computers and sites like facebook.
Personally, I hope this never becomes an accepted practice. If it does then what about people like me who don't use facebook... They're highly likely to assume I'm just lying when in fact I really don't have a facebook account. So they're probably just going to ditch any applications I put in because they think I'm lying.
And for those that use the second account tactic, employers would probably wise up to this quickly. Especially if an account doesn't look like it's been used for a long time or it's only for businesses and stuff. They'd porbably just dismiss it, and the potential hire if they feel like they're being lied to or jerked around.