Several comments. First off, I read the article, watched the video, and formed my opinions before reading a single post here.
James Woods does not always post things I agree with, but this time I completely agree with him. Cops are out to make money. If it were for public safety, what she did had the same result. It slowed people down - or not. How many people take the time to read signs people on the side of the road are holding? Most people think they are begging for help and just avert their eyes and pretend not to see them.
Slowing down motorists doesn't stop cops from pulling them over for a broken tail light. It only stops them from giving you a speeding ticket. In fact, it probably gives the cops a little more time to check out each car and see things like broken tail lights.
Arresting her is retaliation and giving her a trumped up charge is inexcusable for a law enforcement officer if it was false. 99.99% of the time, I'll bet he never writes a ticket to anyone for stepping on the street. If he even bothers, I bet he just gives a warning. An arrest is way overboard.
Cops and cities are corrupt. I once got a ticket for running a red light. After doing some timing of lights, the length of the yellow at this intersection was very short. Shorter than other yellow lights on slower streets, shorter than at intersections with less traffic. The shorter yellow only increases the possibility for accidents. Yet increases the potential to give out tickets. Like the red light cameras, what is the purpose, public safety or city revenue?
Now you can argue, perhaps, that giving out tickets may provide negative reinforcement for the driver and prevent them from repeating. And more effectively than seeing her sign and slowing down might do. And I can see that.
As for stopping people and catching other things, that to me sounds like illegal searchs. You have no probable cause to believe they might have drugs for instance so you can't stop them. But dammit if you aren't going to stop them for something so you can search them. This to me is an abuse of the system.