At one wedding I was at recently, all the groomsmen gave a knee-jerk Christian bit in their speeches. It was a little bit sloppy and I heard a few sniggers at my table from slightly drunk people who noticed the change of pace in the speeches.
In another wedding I was at recently, the Christian preacher didn't give an explicity gospel presentation or appeal at all, as far as I could hear. The sermon was well composed and delivered and came in the context of a marriage service drenched in biblical, gospel-shaped prayers and preambles.
I think both approaches have their own sort of class, I don't favour one over the other. Besides, the groomsmen will get less sloppy in their devliery with time. For me personally, I would like to knee-jerk to the gospel a little more frequently. I like the openness and eagerness that leads someone to grind from fourth gear down to second in order to talk about Jesus...