That would be a tragic mistake for everyone involved. People like being in on the joke when John Cena, a grown man costumed in neon green, runs around the square stage whilst pretending to be invisible. It would ruin the fun if his opponent unceremoniously dropkicked him in the solar plexus.
The Undertaker: Long Term Story Telling in Wrestling : https://www.youtube.com/watch?v=xHVCTOmQNZM
Professional Wrestling is Stupid and Beautiful and I Love it : https://www.youtube.com/watch?v=BQCPj-bGYro
Not to take away from the point, but I could also see this being part of the joke. "No, obviously you're not invisible! Why did you think I would fall for that?"
The point is that WWE broadcasts are specifically about fun and entertainment. It's not supposed to be "real". (Although, obviously it is "real" even if it's staged; imagine doing what they do and not killing or injuring yourself or anyone else.)