If you rent your router from Comcast you need to know that they are and have been disabling the lock feature that keeps others from using it. This means that people can line up in front of your house and tap into your router with Comcasts blessing and there is little you can do about it. The key here is you need to purchase your own.
http://techcrunch.com/2014/12/07/co...ore-difficult-to-opt-out-of-internet-sharing/
http://techcrunch.com/2014/12/07/co...ore-difficult-to-opt-out-of-internet-sharing/