[@Aristocles]The idea of a sort of Spartan "secret military police" is an interesting one. While that isn't something mentioned in lore, it is something I could certainly see an organization like ONI authorizing. Spartans themselves are particularly loyal (except maybe the IVs. They are just the normal sort of loyal.), so it is not likely that he would have ever had to actually carry out those secret orders on a Spartan, but it's not farfetched that ONI might want to have operatives willing to do that, just in case. 

One note is that the Spartan-III "companies" aren't really organizations that one could be assigned to. They basically just represent the generations of Spartan-IIIs. Alpha was trained first, Beta second, Gamma third. It doesn't really change anything, though, since your character could still have been assigned to a variety of Spartan teams with that same mission. It's mostly just semantics. 

I don't mind people getting creative as long as they don't directly contradict lore, or do anything [i]too[/i] crazy, so it seems to be fine. It will be interesting to see if people get nervous having a Spartan looking over our shoulders.