There's just such a big gray area in this topic since there's no physical boundaries that the naked eyes can see when it comes to wireless network range.
How's this scenario. You have "default" as you primary SID since that's the name of your home's router. You also set one of your SIDs to T-Mobile (or whatever it is) since you're a T-Mobile hotspot user. You go to a T-Mobile hotspot to connect to the Net but there's another open network within range that happens to be named "default." Of course, your card picks up the "default" network since it's higher priority. Of course, to a novice user or even an advanced user, there's no way to tell. So, you're technically breaking the laws when you're using the "default" network even though you're thinking you're just using the T-Mibile hotspot. Is it fair to the user? Of course not.