My BF went to Denver a few weeks ago and he was told by his employer here in Germany (a Boeing spinoff company's German office) to tell Immigration that he's there just for meetings NOT work... go figure

I recon everybody needs a valid working permit for the US if he's not a US citizen or has a Green Card.

Here on the Axis of Evil's German Branch we have a permit specially for "Arts" related issues such as photography - y'all might have the same stuff in the US as well.

Chip... if you shoot in Canada, do you need a canadien working permit?