One particular occasion, while lying in the paralysis state and struggling to wake up, i began(with what little movement I could) tugging at my sheets with my hands, I noticed that I was lying on top of most of my blanket as I was squirming, trying to "wake up". Upon waking, I was comletely covered and my blanket wasn't disheveled in the least. Moreover, I've read this account of one person's experience with SP.
Violent Ghost Attack in Dream - Real Ghost Stories - Your Ghost Stories
It further strengthens my beliefs on this experience, at least for what "I" deal with. I've never experienced quite the visualizations of this account, but the general idea is in tact. Who knows, all cases may be different, there may be some that do see the real, but for me, I'm convinced of this being a dream state that just seems real.