As a rule of thumb, GWs rarely allow any leeway to a hunter/fisherman, hence their reputation. To most of them, there is only black and white when it comes to the law, no gray area, no exceptions.
I personnally wouldn't advise testing them in the field. Worse case scenario, you lose the ordeal and take a chance on losing your hunting/fishing privileges for life.
In the case mentioned above, just smile, inquire as to what the law is in regards to feeders, then nod and say "I didn't realize that, thanks for letting me know, Sir."
Then, as he drives away, you can call him an "a^%hole!"
And you go back to hunting.
