And surely they'd never mislead anybody regarding what data they keep.
Which admittedly makes it a bit hard to explain how, despite having completely deleted my account several years ago (yes, not just deactivated, I went through all the little guilt-trip pleas not to delete), they managed to accidentally (a bug, presumably) send me a Friend Suggestion email several weeks ago (suggesting someone I actually do know, no less) considering that by their own words they should have wiped both that email address and the social graph associated with it several years earlier...
Oh, you mean the account that you confirmed as deleted 8+ years ago??