Cheers! You don't really get into any trouble unless you walk around carrying weapons or something crazy! Even if caught in an MOD place the most they do is tell you off and escort you off site. Anything else is just hired security and they just walk you off site.
It does require some experience though with the people you visit with, a lot of team work involved and research and planning!
Depends what his job is really. I could lose mine if I was even cautioned, as government contracts are VERY strict. Ironic really when you see the crap MPs get away with.