1. The taxes at issue here are YOUR STATE'S taxes. It's not you (as a resident of State A) being forced to pay State B's taxes. The question is under what circumstances a business can be forced to collect State A's taxes for purchases made by residents in State A.
Perhaps, however I live in New Hampshire (which has no sales tax) and was forced to pay another state's sales tax when I purchased a gift and had it mailed to the recipient. It has nothing to do with MY STATE'S taxes. I was forced to pay State B's taxes or else deny the sale. As it was a gift, I went ahead but it's not like I got anything for my tax dollars. Talk about taxation without representation.