Regardless, and maybe it's not a great distinction, I find a difference in a company not charging sales tax vs a company sending an excited e-mail about how they've found a loophole to avoid sales tax. Maybe that's just me.
Instead they "withhold," helping themselves to an interest-free loan and obscuring the bill so the average Joe grumbles a bit sometime when he sees his pay stub but has little awareness of his actual tax liability; then he jumps for joy at his "refund" April 15 when the government kindly returns his money that was never theirs in the first place. Hooray!
I thank God this is not the custom anywhere in this country for general sales taxes (all state and local). All "having to show the final amount" means is that the tax is hidden from the consumer in his day to day transactions, instead of staring him in the face every time--even requiring some quick arithmetic on his part. The last thing we need is even less awareness from the public of just how much of their money the government is taking from them. (Income tax withholding has already done an excellent job of that.)
I am constantly shocked, in fact, that in the name of "consumer protection" our politicians have not already hit upon this ingenious way to increase taxpayer complacency. Give it time, I am sure--especially since "being like other countries" (only insofar as they have more government involvement in their citizens' lives, of course) is the increasingly open and fervent declaration of politicians over here.
And in fact jurisdictions around the world and throughout history have typically done essentially exactly that--when sales taxes exceed a certain number (I think it's around 12%) they switch to "excise" to temper public awareness and outrage. And then the dam is burst; they can hike all they want. No thank you.