Although I'm pretty sure that you could use that image for any number of reasons, most notably that they have to SEE it first before they could have a problem, I think that in this case it would be polite to ask them. Most people and companies, are REALLY flattered when you use images of them, as long as they're asked.
I had a particularly good looking bride jump out of her chair when she found out that I wanted to use her wedding in my wedding portfolio, "I made the book! I made the book." were her words. But last week I got a phone call from a mom who was pissed because I used a shot of her flower girl daughter on my web site.
Actually I'm not quite sure HOW I'd go about getting permission from everyone at a wedding. I do have a line in my contract, such as it is, advising the B&G that I retain the right to use any of the images for my own self promotion, but that wouldn't apply to anyone else. In any case the mother snarled for about ten minutes but made it clear that I could continue to use the shot of her kid. I of course had it removed as soon as I could. Otherwise the mom is going to cal all of her friends and, a) point out the great shot of her kid, and b) slag me while she's doing it. Removing the kid has put an end to that possibility! With a little luck I'll get a call from her soon asking where the kid went!
I'm pretty sure that this is off topic but my advice would be to forget about the legality and just ask.
"There's never time to do it right. But there's always time to do it over."
Canon 5D, 50D; 16-35 f2.8L, 24-105 f4L IS, 50 f1.4, 100 f2.8 Macro, 70-200 f2.8L, 300mm f2.8L IS.