You stop lens "flare" in a wireless camera the same way you stop it in a wired camera. Glare or "flare" is caused when a bright light reflects off the surfaces of the inside of the lens. It's caused by a light that is too bright compared to the rest of the scene. It can be controlled by using a lens hood or aiming to get the light away from the view of the camera. It can even be a light source that is not seen in the viewfinder. See this article.