Who is going to go around making sure every seatbelt is fastened properly? Is the driver going to have to get up and buckle each one in at each stop?
Will they hire a monitor to do this and some stops have multiple children getting on, how long will the buses be stopped at each stop. People complain about being stuck behind buses now just think how they will complain then.
Depending on what area you are in some kids may beat on each other with them.
Some kids might get a kick unbuckling theirs or others over and over again.
Also if the bus is full of smoke or goes into the water who will get all of them out if they can't get unbuckled.
Seat belts sound like a good idea but for buses not so much.