Although I have barely scratched the surface of the topic in my reading, I didn't know there was any way to test the existance of alternate universes. Mostly because I thought any interaction between universes would mean that the 'other' one was then somehow part of ours, or else we couldn't interact.
Always amused me how certain scientists arch their back and rasie their fur at the mention of God, because a being with infinate power whom you have to take on faith just ain't science. But if infinate, unprovable universes help solve your equation, or publish your paper, then by all means, throw 'em in! Suddenly it's great science!
Black Hole Deniers! I like it!
I agree with your next two paragraphs also. On this subject I think we think alike. (Great minds?)