Yes, many sites already have it, RTA is nearly 3 decades old. It seems new proposed laws always ignore such systems are not just a theory but in a reality in use.

What happens over and over only reinforces they idea that they really want "everyone, empty your pockets and show your papers, NOW!" laws and just hide it with "it's the only way, trust us; for the children!". A pretty telling proof is they want to be exempt.