If people are worried about anominity, why doesn't the people who run the jet2crew website have a private section that only BALPA members can access. In order to gain entry you must have a valid BALPA member number! This alone will generate LOTS of interest from non members!
It can't be too hard to set up a forum within jet2crew that is password protected for BALPA members only, and invite a BALPA representative from BALPA head office to monitor this section. That's what happens at other airlines
That way, the CC can see just how many BALPA members they actually have, and the private forum could also be used to thrash out problems out of the eyes of prying management....????!!!!
Only a thought....