I can see both sides of the argument but in the case that the family is not travelling with the person who earns the benefit, in my -personal opinion- they should not be able to bump someone who actually works directly for the company... yes people have worked here for a long time, they earnt it, etc etc etc... but it doesn't seem fair that someone's maid can get priority in y/c over a ground staff or gr2 who is employed by and paid by the airline, over someone who is employed by and paid by... an employee...
Our kangaroo friends I believe work on this principle (or used to) a beneficiary of staff travel cannot bump an actual employee unless also travelling on the same flight as the employee earning the benefit.... the system is transparent and displays the staff listed so you can tell whether to bother or not... might have changed but it seemed fair at the time.
At this rate the staff travel is not even worth mentioning as a 'perk' because for any of us lesser than captain, you can't use it except for ALT, id50 isn't even worth bothering with because they still give you AB if you get bumped through their overbooking and can't get back to base (despite the ST manual saying otherwise) They overbook by 50+ in Y these days and leave crew on confirmed id50 behind... tell me how that's fair...