This happened to me. I had a thread about it somewhere. Or, maybe not; maybe I wrote about it on my blog.
It turned out to be just fine--there was a "gift revealing," but no unwrapping. Which made it all go faster. And since in my ILs' family, showers are 70 people if they're small, you really could spend a lot of time watching her take the wrapping paper off. And the gifts are all in a pile, so it's not like anybody gets to admire any wrapping paper.
I'll admit--I cheater. I bought a set of nylon grocery bags, ironed them, and put her gifts in there. So, I *sort of* wrapped them. It made me feel better.