It is fun, but I figured out that as much of a problem as it is, some of these places view you as a hacker that has made some malicious move on there network no matter how you present the security flaw to them. They usually claim they will have someone internally fix it, then they don't do a thing about it. I have seen it over and over again. In fact, a rather large grocery chain locally (biggest you can think of) is wide open on many of it's stores, DHCP running, broadcasting the BSSID, no authentication etc. Any kid with a wireless card and laptop can play on their networks while their mom is in shopping. Was the head security guy in shock? Of course. Did he say he would fix it? Yep and 2 years later, it is still the same.
It stopped being amazing to me after I figured out that no security is the norm and no one seems to care even if you tell them. So rather, I just consider them useful internet connections when I am away from my own.
On that note, somebody buy my Libretto

Think of all the fun you could be having!