I noticed on Butterfly labs' website that they say that they're collecting sales tax for all US orders...how can that possibly be right? You'd have to have a business presence in all 50 states to be required to collect sales tax in all 50 states, and you'd have to remit sales taxes to 50 different states for which you'd need to have 50 sales tax certificates. Unless they're actually sending sales taxes to 50 different state tax boards plus calculating the tax rate for every county in all 50 states they're breaking the law. You can't just charge Missouri sales tax on an interstate transaction.
For people who ordered, what sales tax rate did they charge you?
Technically, they only need to collect sales tax for states in which they have retail presence, or in which they operate. I don't know why they are collecting sales tax for all 50 states. The government is trying to change the laws so that sales taxes would have to be collected for all states even for online sales, but last I checked, they had not come close to pushing that through.
But yes, if they are collecting sales taxes for all the states that charge a sales tax (even though they don't have to), they'd better be submitting those taxes to those states or they'll be heftily fined!