Why would you have an unsecure network?
There are hoardes of people (I used to be one of them) that drive around for the sole purpose of finding networks like yours and either mapping them out and abusing them, or simply mapping them out to share with others on the internet, or simply abusing them.
I used to own a satellite dish that had a wi-fi USB dongle in the centre of the exact focal point of the dish so that I was able to pick up wi-fi signals from peoples houses that were several blocks away.
My point is you can get any number of network issues with the way your set up is at the moment. I'm surprised someone hasn't connected to your printer and printed out 1000 pictures of a massive cock. That was always my favourite to do to people.