Someone’s planning to propose at my wedding...

So I heard from one of my bridesmaids that one of my guests is planning to propose to his girlfriend at my wedding reception. He’s a friend of my fiancé’s but I’ve never met him. This guy has not spoken to either of us about this and neither of my fiancé want this to happen. We’re getting married with a small group of people, which is mostly family and some friends. This particular friend wasn’t even supposed to be invited (my fiancé hasn’t seen him since high school and that’s was over 5 years ago, but his mother invited him without permission). So a proposal will not just go unnoticed. And as shallow as it sounds, this is MY day and I want my fiancé and I at the centre of attention. We’ve spent a lot of money and so much time on this wedding, not to mention all the years my fiancé and I have been waiting for this day. I want it to be about us and no one else. Would it be so wrong to tell this guy not to come if he’s going to propose? My fiancé thinks we should tell him he can’t come at all because he wasn’t even considerate enough to clear this with us first. But I feel so horrible about rescinding an invitation. Especially when tickets to get there have very likely been purchased already.