I have OCD, with some agoraphobia issues myself. I work at home and cannot go to the store or out without my DH, my oldest child, or one of a select few friends. When I went on the cruise in January with my cousin, we brought along a friend because of my problems. I would not have sailed on any other line but Disney. Somehow, WDW is a "safe zone" for me mentally.

I struggle to get on a plane...my wonderfully understanding husband used to drive 2 days to WDW and 2 days home, just so I didn't have to fly. Funnily enough, one of the worst attacks of agoraphobia I had was the first time I quit smoking. I was afraid to leave the house completely and had to get some Ativan just to go outside for the mail.
I would not presume to understand your life, as I do not have physical limitations in addition to my other problems, but I do understand somewhat, at least the fear part. I especially understand that no amount of people telling you it is "okay" and "perfectly safe" is going to help. My DH and family do alot to accommodate and help me out. I, too, feel horrible sometimes, thinking they would be better off without me to deal with. But the truth is, they love you. They want you on vacation with them. The new policy is just a bump in the road. They will adapt to it. Don't let it make you stay home.