I live in Canada and we do the same thing here. I think it’s a good thing to remind everyone of sales taxes at checkout time. Sales taxes are regressive taxes. We should get rid of them in favour of a more progressive tax, such as land value tax.
Laws that mandate hiding sales tax by including it in the advertised price only serve to entrench a tax that should be repealed.
Edit: I just wanted to note that the vast majority of people I see defending sales taxes (i.e. VAT) are Europeans and the people opposed are North Americans. Putting aside the argument over whether it’s a good idea or not, I think this is good (albeit anecdotal) evidence that hiding/showing the tax in the purchase price at checkout affects people’s opinion of the tax.