I would disagree. If you work in any position that requires a clearance or will at any point (the further your career goes the higher the probability) it's far easier to be honest out the door and skip any headaches. People you think are your friends or colleagues, will dime you out when OPM sends someone to interview them. Let's also not forget that OPM will interview people that don't like you. Anyone with a clearance can actually request their adjudication documents and you'll see things you would never have expected.