Is it something Alvarez should step away from doing in future fights? I see quite a few fighters targeting the left collar bone of fighters in order to get them to drop the left hand. It clearly wasn't working and I can't seem to work out why you'd go for someone's arm rather than the aforementioned collar bone? Discuss.
It's easier by far to hit the arm than the collarbone, Bivol and other fighters (Me included) use the arms as defensive weapons, as padding. If somebody can actually hit me in the collarbone, I'd wonder why they didn't just move up some inches and hit my chin. Your shoulder and stance protects your collarbone naturally.