Hi,
I dont know if that is true butr I saw comments on another forum from people saying that RB works different from Zazzle. Working with Zazzle, is pretty much like you are an artist licensing designs on their products, and you get paid royalties, so you are not seen as a "seller" or manufacturer whereas on RB is like you would be paying them for the printing, and people where concerned that this way is like you end up being the seller who just paid a company to print these products. I don't know if that is true but some people where concerned about the tax side of things. So I guess is best to check with RB to see how things work.