If you're using one of the wide laptops, I could see where tray space would be an issue, but my 12in wide laptop leaves plenty of space on the tray for my mouse.

I've used a wireless mouse for almost two years and never been asked to turn it off. Probably b/c the range on these things is pitiful, at most 2-3 feet. In fact, if the tray table has too much metal in them I've found the signal to the mouse is blocked.