I dont think so. Following that logic people would stop playing altogether. Stepping into the enclosure increases your chances of brain damage vs not doing so.
I'm not saying people would catapult themselves into other people's shoulders with complete disregard to safety. What i am saying is that if shoulder vs head contact = penalty +card, ball carriers can exploit that to their advantage given that they have a huge saying on whether that contact happens or not. I feel we are leaving defenders with very few realistic options.
Picture this. World cup quarterfinals. 2 minutes to go, you are two points down. You are 14 against 15, you have the ball in the opponents 22, but they are holding strong.
If you tell me ball carriers won't look for that sort of penalties then you are way more optimistic that i am.
We (myself included, of course) as fans are a tiny bit hypocritical when it comes to this. We complain and claim to be worried when we see some stats but then we applaud when a player puts his body on the line. We take it as an example of commitment.