The intent of the additional base for an intentional carry is to prevent deception by the fielder to stop a runner's progress. But the usual application of unintentional is a carry resulting from momentum or the above tagging a runner who is in DBT.
I agree with the above "rulings" as long as you are comfortable with the fielder's intent or lack of it.
Personally, I would make the rule such that a intentional carry to stop a runner is a live ball, with the runner protected for at least two bases.
