I'm always a bit nervous about sending out too strong a signal. Even though I have state of the art security there`s always a possibility that some evil-minded hacker could get into my system. So I turn it off when I`m not using it and keep the modem in a place where the signal is just adequate for the laptop in the next room.
It's a good point. Using the most secure log in system goes a long way to ensuring that your system is intruder proof. Using a MAC address permissions table where possible and convenient is also an excellent further step.
Regarding levels of RF power and its effect on people in the vicinity, that's a subject which could involve a lot of ongoing discussion. These days we live in a world of almost constant RF exposure. I would still be more concerned about the long term effects of my constant companion mobile phone than that which involves the use of my WiFi system, even if I had the need to concentrate the signal on any given area where humans abound (which I don't). It's a big subject on which the (informed) jury is still deliberating!
I suspect that mostly, it's considered to be OK at the exposure levels encountered in the average home or office. However every so often information comes to hand which gives rise to some angst.
respectfully,
FOR