i havent put one on the front of any of my new cars and i've notice most people with nice lux cars here dont do it. i guess you drive at your own risk but typically the cops are not out ticketing cars for this. however if you are pulled over for something else they could write you up for that as well.
seems like i read something recently where the last legislation re-wrote a existing law that had plate rules in bedded in it and forgot to include the two plate language in the rewrite and it was passed. i dont how much this argument would go over but its probably valid for anyone who wants to put up the effort to try to get out of a "tag ticket".
http://thenewspaper.com/news/36/3656.asp