Doing this kind of reinforcement training to someone without their knowledge is characteristically disrespectful if you just do it to help them, but it may also be the right thing to do in some cases (I'm toning down my claim a bit).

I wouldn't necessarily say that. Doing it when you know they don't (or would not) want you to is disrespectful.

Doing it with the result that they are harmed is vicious (that is, an expression or manifestation of a vice) regardless of your intentions.

This definitely seems false. It is the expected result, given information that you have (or should be expected to have) that can indicate viciousness, not actual results. For example, I could reward my children such that they never Jaywalk (still not quite sure what this is) and only cross the road at official crossings. Then one of my children gets hit by a car waiting at a crossing when they would have been fine crossing the street earlier. I haven't been vicious. My kid has been unlucky.

It the general case it is never the result that determines whether your decision was the right decision to make in the circumstance. It is the information available at the time. (The actual result can be used as a proxy by those with insufficient access to your information at the time or when differing incentives would otherwise encourage corruption with 'plausible deniability').