[shamanNS]

It is not unreasonable to expect to either have a prominent indicator that the price listed doesn't include taxes and to expect that globally chosen address that already filters out what can and cannot be shipped also at the same time "informs" the listed price (and for that price to be the actual people are gonna pay for that product, + shipping) . And if or when user changes shipping address then update the price and display taxes amount.

To me this amounts to dishonest advertising.
And no, no common knowledge and facts should be assumed when shopping for stuff. If there are taxes indicate right away that it is so.