APU i'm with you on this one.
My understanding is that priority works by job grade then seniority. For a start cabin crew are not allowed to buy business class tickets but flight crew are. What's the point in allowing a person of a particular job grade to buy a business class ticket to be bumped off by a fellow staff member who bought an economy class ticket (unless for business reasons) - regardless of the seniority, you bought a different ticket, if complimentary it's different. Also I'd like to see a senior Training Capt who has to get back to Doha for work being bumped off by a less senior Cabin crew... you may say the rules are the rules... but as I say I understand the priority is job grade then seniority.
In reality as far as I'm concerned... yes there are circumstances where you may be forced to take a flight where bookings are 'tight' but I'd always check the load and try and avoid it.., also if you're flight deck you can take the jumpseat anyway.
I was also told people on the privilege pass only retain the same 'status' as the employee if with them. However there is another 'sub-category'... Annual Ticket which immediate family members do get where the rules change with or without the employee.
A simple call or visit to Staff Travel can clarify all this.