This is something that I encountered on our trip in May. For the first few days, my drivers licence was getting refused more often than not and we were told countless times that they would only accept a passport if you didn't have a US ID. This was a huge turnaround compared to 2011 where out of a total of three months, my drivers licence was refused just one time in Bongos in DTD, and never in a park.
So, wanting to still sample all the beautiful cocktails or to cool down with a beer this trip, I just started to carry my passport around with me. I think the worry about losing it was with me for all of 20 mins before I realised that I'm pretty vigilant with my bag anyway containing camera equipment, money, bank cards etc etc so what was going to change now it had a passport in it? It's just about looking after your possessions.
So, as someone who would never go without a bag, then I have to say that this really isn't a big deal to me. For those who won't take a bag, then there are always money belts. Them's the rules now it seems. It's obviously being implemented for a reason, and a few CMs chatted to us about the fines and penalties in place if they were caught selling alcohol underage. I assume the change in policy is partly due to this, and standardising the process so that only passports are accepted, well that's ensuring that the staff are looked after. A PP said that WDW should put the guest's needs before it's employees... How nice.
I have no problem in complying with this. I agreed with the majority of you previously; I didn't fancy carrying my passport around with me. But after doing so this trip, then it doesn't bother me now.