Too many instances to recall when it would have been justified for Christopher to get whacked. I agree you can argue going back to the pilot episode.

But one of the first instances was Meadowlands, right after he found out Brendan was killed. He comes into the Bing screaming and it was just after the news came that Jackie Aprile Sr. died. Had the setting been in someone's house, where there were less "citizens," Tony would have whacked Christopher right then and there.

Fast forward to "Long Term Parking," I think it would have made for a more fascinating storyline twist if Christopher was whacked WITH Adrianna.