Dirtleg, I think you hit the nail on the head. From a business standpoint it really is a no brainer. But from a guest's view it is a completely different story.
The year before last, when we were at CN there was a fairly large wedding party, I think about 40 people. They night before the wedding they did have an area roped off for their rehersal dinner and of course the next day for the wedding and reception on the lawn by the gazebo. But after that they just sort of blended back in to the rest of the resort, I do think several left, I am not sure. But we only saw a few of the couples, including the parents of the bride over the course of the next week.
I don't think that there is an easy answer at all. I do wish that they could or would monitor singles a little closer as well. There was a group of 8 from Tenn at CN last summer. Of the 8, 6 were part of a couple, but other 2 were the single daughters of one of the couples. At first we thought they were there for a wedding, and they might have been, we just didn't see them at any wedding the whole week we were there. Even if they were that is more then the 5% of the group, closer to 25%.
Before you criticize someone, walk a mile in their shoes. If they get mad, you will be a mile away and they will be barefoot!