Gavia wrote on Jun 17^th, 2013 at 2:53am:

Solus wrote on Jun 15th, 2013 at 12:45pm: Not a chance. My pfd draped over an appropriate slab or log becomes a lounger. I don't want to be too obnoxious about this, but sitting on your PFD will crush the flotation, which will make it less useful if you ever need it for its intended purpose.

My PFD (as most modern units) is filled with closed cell foam (air sealed in foam- will not be compromised by compression) in vertical "ribs" encased in nylon. It is not in the least bit compromised by sitting or standing upon it, it is uncrushable.