Over at Patheos Christian Piatt has a piece in which he describes his experience at a Gay Pride parade in Portland where he and his wife wore sandwich boards with the following message:
According to Piatt, humbly begging for forgiveness from the Gay Community on behalf of all Christians (whom, it's worth noting, he doesn't necessarily speak for) in Portland at a Gay Pride parade is a daring act of courage that could possibly carry dire consequences. Consequences such as, I suppose, being accepted and extremely well-liked.
If you carried a "Homosexuality is a Sin" or a "Marriage is a Sacrament, Not a Right" sign, then you'd be taking a stand for the faith which almost certainly would get scorn and derision directed at you. Not that I would recommend such a tact, but let's be honest about what is and what is not an unpopular stance at a particular venue. There's scarcely anything safer or more in line with current cultural trends than gestures toward the LGBT community in this vein, especially at a Gay Pride parade in Portland.
This fact in itself doesn't mean that such gestures are wrong (though I think they are), but even bracketing out that question -- and saving it for another blog, perhaps -- it's objectively not the case that it's a stance very likely to cost you anything. Not even so much as being mildly disliked.