Well I've certainly seen the arguement on here from some Creationists along the lines of "well.. millions of people can't be wrong"
I however. think they can
But I think it is certainly true that for many people who would be, lets say, a borderline creationist, the fact that more people would follow creationism may move them towards that belief system. I suppose it could be interesting to note conversion rates for all religions, and see if proximity to large numbers of devotees affects the likelyhood of an individual of converting to a particular doctrine.