My understanding, gained by personal research ten years ago, is that as a non citizen visiting on a tourist visa, not only could I not work, I could not investigate business/investment opportunities, nor could I even do voluntary charity work such as help out in a soup kitchen.
Basically, if your activities could be construed at any level as doing what otherwise might be paid work for a legitimate local (citizen, green card or correct visa), then you are in breach of your tourist visa conditions.
But then who takes legal or immigration advice from a pilot's website?