In the parks? I'm not sure they're willing to chance potential lost purchases. I was surprised to read that they were getting rid of plastic bags in the parks altogether -- erroneously reported elsewhere.
I'd guess people would break down as follows if they moved to no plastic in parks except for purchases sent to the front of the park, sent to the hotel, or sent home:
1) Who cares? I'll just buy a bag with every purchase, or bring my own. Yippee!
2) I will buy less in the parks for whatever reason (refuse to bring in or pay for reusables in parks, principle, etc.)
3) I never used to send to the front of the park, to the hotel or home, but I will now.
2) or 3) are bad for Disney. 2) results in lost sales. 3) results in increased manpower costs. I could just raise prices to account for 3, I guess.
I think the OPTION buys them the PR and brings in extra bag revenue. Keeping plastic avoids annoying those in 2). Seems to me like the best place to land. But know knows, these days?!?!