The RAF (and RN) personal numbering systems are different to the Army's. If the RAF pers checking ID have not seen many FMOD90s they may well not be aware of the difference in Officers' and ORs' numbers.
I remember arguments occurring when, in NI, the Royal Marines on the gate failed to pay compliments to Army officers in civvies - they said they didn't know that the numbers were different.
Realistically, how many junior ranks on gate duty would think of questioning someone in an Army officer's uniform, who says they are an officer and has a genuine FMOD90?
RAF ID cards show the rank of the holder, which seems a fairly sensible way of showing the difference between Officers and ORs.
Don't the crabs have the little poster in the gatehouse that we used to have? The one that shows what a genuine ID card looks like, be it Army, Navy or CivForce as well as the differences between Orrificers and OR's ID cards.
If not, I'll have to remember that the next time I want to get into RAF Cosford for free, I'll just knock one up on Photoshop.
The poster is probably there, but I think it's human nature to look at the whole picture - visitor says she's an officer, is dressed in correct uniform and presenting a genuine ID card - most people wouldn't go and check the poster. In any case, it was probably the MOD Guard Service that let her into Valley.
For several weeks I went in and out of a Bde HQ in Germany with the wrong car pass - I had two cars and hadn't noticed that I had mixed the passes up - all the sentries saw was that it was the right colour and had the unit logo....
If you're doing some Photoshop cards can I be Sir Mike Jackson?