Well, perhaps a lot of things that are legal can be used illegally.

I can see the advantages, but don't have a use for one

Although when were considering setting up a wireless network to access a cable signal it would have been nice to know about it.
Remember Scott's Starbucks article?
[quote]is that his company's inexpensive antennas could be used to create ubiquitous Wi-Fi coverage by linking and extending the range of existing and soon-to-be-deployed
public and freenet access points.
Seems like the guy is pretty pragmatic. He figures they will be regulated but at this point ...