You definitely have to be careful with the type of shorts if you're doing it.
lyndsay_h - you cracked me up there! I think more than a few hubbies think board shorts would be ok for a wedding, thank goodness we don't let them. (Unless you were in a bikini getting married on a boat - that's a little too Pam Anderson style for me :S)
My brother in law wore his favorite grey linen shorts for their wedding in Barbados (just the two of them) with some nice brown leather sandals (I call them his mandals) and I thought their pictures turned out great. I'll attach one so you girls can see.