I think the point of the thread is being missed by some, this is not about commuting or the rights and wrongs of it, EASA FTLs etc. It is about pilots commuting in their own time in uniform by suddenly becoming part of the crew.
This allows them to use staff search (explicitly forbidden by the dft unless they are on the gendec as part of the operational crew or as supernumerary crew). If they are using this "loophole" then surely they must travel on the flight deck (can you be a supernumerary pilot in the cabin?) be on the pre departure paperwork at the brief and not just arrive on the aircraft and be added to the crew list just prior to departure AND it must count towards their FTL as they are now on duty and it is therefore a working day. I just don't see how this is legal (not withstanding the "perk" of free travel which I a sure the tax man would be interested in as a benefit in kind).
I am a commuter by choice (GLA - LHR) I have to buy a ticket (staff or full fare) and I have to use passenger search in accordance with dft rules, I would lose my airside pass if I used staff search (my company put out a notice about this last year warning it was a disciplinary offence).
I would be interested to know if any other airlines in Europe and specifically the UK allow their staff to travel in this way.