It is quite common to carry civilians in military aircraft BUT it requires a specific authorisation (used to be called a "civauth"), normally from a specific office in HQ.
110% that DM knew he was doing wrong!
Reminds me of the kiwi C130, in the early 90s. The crew met a few lovely ladies in Ireland....and flew them, and their car, across to the UK for an airshow.
The MOD police were far from pleased that a few Irish and a car managed to get onto and RAF station through the back door (as it were!)