Most "security" cameras these days seem to do just that, be connected via pretty open WiFi and no other connection options.
insecam.org (IIRC) or shodan(?) can show you the results of buying standard 'security' cameras these days. Many seem to be very helpful to the miscreants, as they can give a clear indication of when you're not home - just sit outside the house, grap the WiFi signals, look over the stream from the cameras... Then to disable the whole security system disable the router (eg change the IP it's DNS client uses to something that does't handle DNS...) and the person who has trusted in their wonderful all-singing etc security system finds out that it actually aided the crims more than it aided them.
(Must remember to get more of me meds...)