Comment by fintler

Speaking from past experience with the DoE (I'm happy I don't need to deal with security like this anymore), there were constant and randomized checks to make sure fiber cables (they were all fiber to make it harder to tamper with and to avoid accidental RF) were fully visible (e.g. not hidden under a desk or something) and not tampered with. Also, lots of locks and doors, both electrical and mechanical. The guy at the front desk with a big gun probably helped too.