Pinch flats: hardtail vs full suspension. Differences?
Honestly this has more to do with how you let your bike "float" underneath you over obstructions than it does with rear suspension or the lack thereof. Since you can potentially go faster on a full suspension over rough terrain than you can on a hardtail I would say you're just as likely to get pinch flats. You just have to unweight the back of the bike and stay loose as you cross rocks/roots/whatever. That's a crucial key not only in reducing pinch flats, but in going faster over technical terrain as well.

Short answer, just as likely on either platform depending on your riding style.