At that point I delete my Facebook account and never look back.
Your employer may not have the power to access those "deleted" records, but there are parties out their that do have access, i.e. Governments and such
As soon as you apply for a job that is high level or sensitive enough, that information will be part of the dossier they review. Depending what is in your FB, or any other comment history you may have, it MIGHT be wise to keep that FB. Lest they think you were trying to hide something.
I need a FB account for work. When FB inevitably becomes so invasive that people begin to panic and delete their profiles, I can safely delete (deactivate) mine. FB may keep all of my data, hopefully I won't have given them anything that isn't worthless.
I think the only safe policy is to refrain entirely from adding any information to the system; you may never get it back. Even seemingly innocuous status updates and public conversations could look suspicious/unprofessional/embarrassing later on.
If you don't mind me asking, why do you need an FB account for work, especially when it sounds like you don't even use it?
Its a real pain in the ass, mixes personal and work way too much. I had a Facebook account already, and i still do, so i didn't mind too much....but i dislike the left overs its causes (installed apps, pages in my name, app keys in my name etc...although this was just due to poor management of these assets)
If you apply for a job that is sensitive enough, they are already going to completely rifle through your personal life.
A step further, and this is where I think I am, is the "delete" option, where you, small 'd', "delete" Facebook, but your information is still there in case you want to come back. It's not accessible to your buddy Joe Blow, but it's there.
Finally, and I might be wrong here, but there is a big 'D' "Delete" option, where facebook deletes your info "permanently" or as "permanently" as they'd like you to believe.
I don't plan on going back to facebook soon, but I'm with you in worrying at times that a sensitive employer would look at a "deleted" or "Deleted" facebook and think "What is this guy trying to hide?"
Also, deleting these accounts does not assure complete invisibility on the net. If you've used your account to comment on a public facebook account or page, there is no assurance that deleting your account would delete that post too.
What's interesting is that the purpose of the background check process seems to be threefold (as I gleaned from talking to an FBI Special Agent who interviewed me about a friend):
1. Identify possible ways in which the investigated person might be manipulated. Having an affair? Had an affair a few years ago which the current spouse doesn't know about? Gambling problem? Drug issues? If so, you might be susceptible to blackmail or bribery.
2. Identify propensities for dishonesty or lack of trustworthiness. Did you cheat on tests? Do you follow-thru on promises? I was asked a lot of questions about how much I trusted this friend.
3. Identify possible 3rd party allegiances. Are you someone identified by the mafia at age 15 as a person who will go to college, look sparkling clean, and then infiltrate the FBI? To make sure, the FBI interviews people from many phases of one's life. It would be really hard to have seemingly normal friends while you were secretly off training with some foreign terrorist organization. I suspect I was also background checked, but I never signed-off on it. The FBI seems to be using the social graph transitively to verify that you aren't hiding anything. No proof of this last statement though.
I've been told that, at least for normal governmental security clearances, the goal is not to determine if you are a good or bad person -- it's to determine if you are hiding something. If your wife knows about the affair you had five years ago, it will be hard to use that knowledge to blackmail you. However, if it remained a secret, you might do something not so good for the USA to save your marriage.
I was asked about the additional names (expressed only as initials due to space constraints) on my friend's condo deed. She had purchased the condo while in law school, and her parents co-signed on the loan. Only after the interview did I realize that the FBI was confirming she did not have a sugar daddy!