It certainly sounds like this guy has gone too far. But any wedding photographer will tell you that it can be a pain to shoot a wedding when the guests are also trying to take photo.
This used to be a more serious issue for photographers because it was common to make most of your money on re-print sales. If a guest happened to get a shot that 'good enough' for the B&G, and gave it to them for free...the photographer would loose a sale. This led many photographers to act pretty surly at weddings, as they were trying to protect their income.
These days, it's much more likely that photographers make their money up front, and/or they sell a bunch of digital files anyway. So the photographer doesn't have to rely on selling individual prints for most of their income.
Another issue, is that if the subjects of your photos, have two or more cameras pointed at them...they may not know where to look. And if the other cameras are being held by their mother and their beloved uncle Bob...they may be inclined to look there, instead of at you. So you end up with inferior photos because the subjects are looking every-which-way.
That's why I have it in my contract that I am to be the only one taking photo. Of course, I don't intend to enforce that policy unless it becomes absolutely necessary. It's usually enough just to have it in the contract and to go over it with the B&G. (and maybe remind them during the shoot).
