"Sir, you can't use the Internet outside the library."Link (Thanks, AKMA!)
I said, "What?" (I'm pretty clever under pressure.)
The officer in question (whose conduct was entirely professional, firm, and calm behind those mirrored shades) solemnly assured me that in order to use the library's open wireless signal, I had to be seated within the library. The officer then wandered on back to the nearby police station.
I dutifully, if reluctantly, turned off the power to my Airport card and, since I had only been on the bench a few minutes, began working -- offline -- on what turns out to be this post. I had noticed two other weak but open signals in the area, and I figured that I could post this perplexing moment via one of the other open signals, then scuttle back to the studio. As I was writing, the officer returned and -- as the officer walked straight for me -- I held up my TiBook, pointing to the zero lines in the Airport icon, and showed the officer that my card was off.
"Why don't you just close that up, sir, or use your computer elsewhere?'
I closed the computer in order not to constitute a threat to established order, but engaged this peace officer in a discussion of the complexities of the topic. "I did notice several other open signals in the area -- am I allowed to connect to them?"
"Maybe if you had permission it would be all right, but it's a new law, sir; 'theft of signal.' It would be like if you stole someone's cable TV connection."