I'm not one for confrontation or campaigning or telling others what to do, so I've tried to think of a sensible way to help this situation...
Unnecessary radiation = bad (let's leave it at that for now)
Most routers, including the most common router in the UK (the BT HomeHub), make it very difficult to toggle Wi-Fi on and off when you don't need it.
The result is that I have about 8 Wi-Fi signals visible on my iPhone while sat in my village home during the day and most of the neighbours are out of the house. At night there are still 6 signals visible.
Even our Wi-Fi gets left on accidentally sometimes, because it's actually pretty difficult to toggle it on/off without firing up the PC and hitting about 20 keys. (BT HomeHub 3).
I'd like to propose something to Router manufacturers.
1) That a physical Wi-Fi on/off switch is provided on all routers
2) That a timer is provided in the router web-interface so that you can easily set it to switch off Wi-Fi automatically at night.
How would I go about getting support for this idea?