I don't think iOS shows the missing plugin box like it used to. It seems that now it just shows an empty box, which makes it look like you're seeing everything. Can someone confirm that they changed this on a software version at some point? It's my experience on the iPad. When I first got it I would run into 4 or 5 sites a day where I couldn't watch the video. I don't experience it as much now because I've trained myself not to follow links to videos at all unless it's YouTube.