The article on this begins with:
"Just as trucking companies put signs on their vehicles asking the public to report unsafe drivers, parents can now put license plates on their baby strollers to get feedback on the behavior of their nannies."
So if you see a nanny neglecting their duties, you can call it in and the parents login to a website with a password to find out if there are any problems. I don't know if there will be any checks and balances. What if a rival nanny calls in a phony charge of neglect (something like this happened with "rate my professor").
Will young people be less likely to become nannies if they get spied on? Will this scare away irresponsible nannies to the good of the children? What about nannies that care for kids who are out of the strollers and buggies? Will the nanny have to wear a t-shirt with the number?