Anyway, I often find myself in the exact same position you describe!
As a professional aviator I have found that it is important that the cabin crew are alerted to the fact that an educated and qualified crew member be available to help in the unlikely event of an emergency.
I find the best way is to ensure you pax in full uniform.
Resplendent in epaulettes, wings and a thick AIRBUS or BOEING lanyard holding my ASIC there is no doubt that I am capable and willing to assist in an evacuation should it be required.
I suggest Sir that even if you are not on duty, even on holidays, that you turn up to the airport, when traveling, in full uniform and you will be given the exit row. (You may still need to undergo security screening but if you are not a frustrated wannabe airline pilot with a PPL and an ego then that shouldn't bother you, so we won't go there
Anywho.. should you require any further information concerning the correct procedures for paxing as a professional aviator, please don't hesitate to ask I am more than willing to help
So just to get this straight, lest the p1ss takers on this thread decide that identifying yourself, and therefore protecting yourself is a bad thing, and btw I'm not talking about being a tw@t here, merely a professional.
What constitutes a situation that warrants your involvement? A little frost on the wing? Maybe a minor fluid leak? Perhaps a remove before flight tag? Or maybe an obstruction inside or out?
I'm just wondering given the shellacking you have given the original poster when in reality he is merely stating the BLINDINGLY obvious. Irrespective of the 50% certification or otherwise isn't it worth a quick check? If nothing else it might save someone's life one day.