No opinion, just bringing background. Info from publicly viewable web pages show, in general, TSOs must be able to pass a background investigation, an LTSO must be able to maintain eligibility for a security clearance, and an STSO must be able to obtain and maintain a Secret clearance. TSM, DAFSD-S and AFSD-S are usually Secret, while DFSD and FSD are usually Top Secret. All should also include a Compartmentalized designation. Some specific vacated positions might require a higher clearance then normal (for instance, a AFSD-S that requires Top Secret). This isn't to say that someone couldn't have a higher clearance then required (previous job, staging for a promotion, etc), yet that should be the bare minimum.

From what I've been reading, having Secret is a key to a door leading to huge job opportunities in the government sector. Top Secret is even better. And loosing it is being shown the door. So it might explain a lot, in that the implied/inferred threat might be if that someone with Secret shares SSI looses Secret. That's a really powerful tool to possess (as an employer).