Surely the exact requirement depends the state of registration?
However all cabin crew /pax ratio I have come across relates to actual number of pax. As stated above 1 to 50.
Most aircraft and operators state a minimum number of cc. So anyone know what the policy of the operator is?
When it comes to things like security the cc are often in a hard place with the legal requirement to do it properly against company preasure for short turnarounds.
That said there are sadly a very small number who take great delight in doing very time consuming "thorough" searches for their own ends.
There is only one commander, he/she is not god but equally should be given the respect that that rank and position deserves. The line respect has to be earned has no place if this is the first time you have flown together. Suppose there is an issue just after you meet?
At this point we do not know the full story and I find it hard to belive that any captain would depart in this day and age with below minimum crewing.
Finally what did the FO have to say? If it was safety related I would have thought they would have had a vested intrest in raising concerns.