I get we are all nerds here who love nothing more than to examine the unlikeliest of edge cases in great depth,and that typically makes us very good at our jobs... but this is all slipping into profound apologist territory.
While there are a vast number of people from different localities laws and regulations here,for most people the issue we are trying to solve here is simple and the surcharge is not tax or regulation based. In particular, when buying vehicles dealer surcharges are one massive entry and taxes are a) already separately listed b) in great detail and c) not typically that variable. Similar with various telecom completely BS charges which are variations of "we need this money to actually be profitable" - which is fine as such,you're a business and need to be profitable,cool. But don't make me drive 50km or spend 3 hours signing up based on advertised price and then add on BS surcharges that have nothing to do with local regulation and everything to do with your business and marketing plan.
that is the problem we are trying to solve,and again,arguments here seem to veer from "let us definitely let the perfect be enemy of the good and not solve anything until my favourite clever unlikely edge case is addressed" , to "shirley I have a vested interest somewhere to be protesting this much" :)
P.s. and then there are Ticketmaster convenience fees and other companies service fees. I want to see somebody stand up and defend them here as a complicated problem and undue business burden and the right thing for the consumer :)