The controversial call outs seem to be more about not square at marker or standing too far back at marker. And no, it would not be a sin bin, it's a penalty or 6 again. We do often say just tackle him and cop the penalty, however the reality on the field is a large percent of tries are scored when teams get piggy backed up field with penalties or set restarts. As a player you hesitate ( especially late in the tackle count) when called out and you are cooked, you would expect cover defence to make the tackle and when they dont, you look like a complete fool.