Amtrak is going to start increasing it's screening of passenger carry-ons on trains. This is an excellent idea for adding a new level of security to a very open target.
This is not a government-mandated initiative. Any business can refuse service to someone breaking the business' rules...(such as sneaking your own popcorn into a movie theater or undergoing a pat-down while entering a rock concert). I don't mind Amtrak checking for bomb-making residue on bags...I don't want to be on a train with one of those bags.
This is the way to handle security issues, not government mandates.