SS,
How can you assume the two perpetrators know what "On Camp" means? Do you know that there is CCTV around that area? - I think that's unlikely around quarters.
Marham has one of the best security set-ups ever by just having one road through it. Idiots like me realised years ago that there SHOULD be cameras on this entrances to the area and the mere presence of cameras (two per entrance) might prevent a lot of ne'er-do-wells venturing further.