Gday freetosee, You must have missunderstood SDAs go anywhere. I went to the memorial a few years ago and I even invited my SDA minister to come along and he did come along to keep me company. Some fanatic SDAs may not go to another church but that would be unusual. I know of meetings where the local SDAs were invited to a penticostal church starting up and where the SDAs were uncomfortable at them speaking in toungs.
SDAs still beleive they are right and everyone else is mistaken but at the same time when they are worshiping with other christians they beleive they are worshiping god. There is no official position with SDAs on attendance at other churches. Barry