> And I was going (ingenuously, naively, stupidly certainly) under a touristic visa because it was simply the only option (more on that later) to go there. > > Refused entrance because I was going to do unauthorised work in the US

I can't think of any way that the customs officials could have known that he was going to do work unless he told them. It seems to me then that the naive stupid thing was not trying to enter on a tourist visa, but telling the officials that he wasn't really a tourist. When dealing with government officials, a little discretion can go a long way.