"New" car seat and booster seat guidelines from the American Academy of Pediatrics

Does anyone follow these guidelines from the American Association of Pediatrics? Two years ago they came out with new recommendations. Kids should be in rear facing carseats until two years of age and older kids should use a booster seat till they are either 12 years, or when they've reached 4 feet 9 inches.

I frequently see younger kids either without a booster seat and sometimes without a seat belt in the rear seat, and occasionally even sitting in the front seat. The comments in this article seem to indicate that some parents feel this is too burdensome for them to implement even though the consequences could put their kids " at risk for internal organ injury — intestines, liver and spleen — as well as spinal fractures.”