The company i work for has used the protective spray for laser prints and the only thing we notice is that the page has a little bit of a gloss look to it. That could be the brand that we are using. I would not be nervous about using a protective spray.
I purchased a can of Sureguard Lustre. It is a wonderful protectant. Water just beads up like a highly polished car. Fingerprints do not show at all. My kid and her friend handled one of the pictures and nothing happened to it. I have just one problem. I am getting a few bubbles (I think) in the finish. Perhaps I am too far away from the photo. I will keep practicing.