They (Carabineros) just want to be sure that you are going in front of the judge and pay your fine. I am Chilean and consider this very illegal but again, a colonialist way of thinking still prevail on a 'somehow' better , almost . developed country.''
In general , Chile does a lot of no sense way to manage the law. To me just complete unlawful by international law. However, you are there and must follow their rules. Better going Monday, pay your fine and go on!
Believe me , some people wait for a bus in main expressways. Sell soda and whatever at Toll plazas in between cars, not beer like in Peru but close. Ohhh but if tohse Carabineros catch you without one mirror they ticket you, Hahahaha!!, sound ironic but true.