If it was a private event and he was crashing it, I say the heckler was in the wrong. But if he really was minding his own business and happened to have a Trump sign handy for some reason at dinner, then that is a different matter.
When I drove by there around 1 p.m. this guy and others were across the street with Trump signs. The event appeared to be outside. The restaurant doesn’t open until 4 or 5. If this guy was interrupting I would think he would have been arrested. The cops were standing 10 or more feet behind him in the the street. Cruz crossed the street to confront this guy from what I read.