Despite your visa waiver, you still have customs forms to fill out and they do ask whether or not you are on business or not. They're very clear that having a

Despite your visa waiver, you still have customs forms to fill out and they do ask whether or not you are on business or not. They're very clear that having a waiver, or even a visa, is not a guarantee of entry into the US and that ultimately it's up to the CBP agents.