Obviously the point of this thread...shoot, it is a darn rope by now...is that the way in which the vendor discouraged photos was the issue. If he had been nicer about it, the original poster might not have had an issue.
But if I may play devil's advocate for a minute, the man is an artist, albeit not a very original one. In order to recreate his art, you would have to do some serious work. However, if this was a painter or a photographer, all you would have to do to have their art hanging in your house is take a picture of it and blow it up: not a lot of effort on your part.
So, I absolutely understand why photographers and painters and the like do not allow photographs of their work. It is a little less understandable for plant makers and sculptors.
And as for photo rules, according to the rules one poster presented, Disney should have NO RIGHT to say we can't photograph a behind the scenes tour or some of the rides.
Just my thoughts.