Most wedding photographers sell reprint photos of the photographs they have taken and this can be a profitable source of income

In fact some photographers rely on this source of income. They might quote a pretty low price for a wedding photography shoot in the expectation that the profit from the reprints  will make up the difference between the low price they have quoted and a realistic price - the price that other wedding photographers might quote for the same wedding.

(Pirates of the) Caribbean wedding

But whether he will sell any reprints depends on what kind of people there are at the wedding.
Some people would rather copy their wedding photographs with a scanner rather than pay for reprints. This is completely illegal in most countries; the wedding photographer owns the copyright for the photographs and copying his work is in effect stealing from him.
Other people are more honest, they will order reprints. And of course this the kind of client that the photographer wants, the kind that he can trust. The problem is, he doesn’t know whether he can trust them - whether they will steal his copyright, until after the wedding.

For richer or  poorer

One solution is for the photographer to just give the bride and groom a CD containing all the photographs that he has taken at the wedding. In other words, to give his copyright away.
Alternatively he can give the bride and groom the CD but charge them extra for it. This extra price can be the value of the reprints that he might have sold to them. The problem with this is, he doesn’t know the value of the reprints that he might have sold to them.

With all my worldy goods

On balance it’s probably easier to forget about whether he might have sold them any reprints. It’s probably better to just quote a price for the wedding, and as part of the package include a CD of all the photos that he has taken.