Rwy, most modern lifejacket don't really have a 'front' and 'back' side... sure the inflation tube is more comfortable facing away from you but most jackets are designed to be put on either way.
(However, the TOP side is pretty clear, except to the guy in the Hudson ditching wearing his pointing upwards! There's a photo out there somewhere!!!
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I think it's true that pax would pay more attention if there's "something in it for them", but again, the novelty would wear off.
I'd let a pax try on a demo jacket, I'd just be discreet about it. I think airlines would be doing a great service to crew to let say, their top 5% of frequent flyers spend a day on an SEP course to see how to do the basics- use a jacket, open the door and so forth. They could then have an annotation on the passenger list that they are an ABP- it's got to be better than a 5min briefing during a prepped emergency!!
Some pax that I fly have more experience than me when it comes to ditching, having done underwater escape courses and thus make great ABPs in emergencies as they have experienced that panic. Something similar for FF's would be great!