They say it is for "serious crime" only, not speeding, etc. and no face recognition, but how easy is it to flip the switch on that? So? What do you think?

State police say the technology would only be used for serious and violent crimes and could quadruple the chances of making an arrest.

These license plate readers will simply capture an image of a license plate and it will be stored in a database for only 30 days. So, if a serious or violent crime happens on the freeway and they have a description of the vehicle, they'll be able to track down a potential suspect.
“It's modern policing. And technology is the wave of the future for everything," Michigan State Police Lieutenant Michael Shaw said.

With dozens of freeway shootings happening every year on metro Detroit freeways, Michigan State Police say they hope this technology will give them an advantage by adding extra eyes on the roads.

“They don't detect speed. There’s no facial recognition. It doesn't take a picture of anybody in the car. It takes a picture of the back of the car and the license plate," Shaw said.

https://www.wxyz.com/news/michigan-state-police-installing-license-plate-readers-along-metro-detroit-freeways