I think it is more of a consequentialist application of Kantian ethics. Kant was all about the motives, and said disrespecting another's human dignity should be avoided because our rationality tells us to respect each other. But, that leaves some strange things open, which may however play into your second point. If someone dies because you lie, Kant says you did the right thing (as long as it was motivated by duty to rationality). I think most people would disagree. But of course, that situation is likely to be rather rare.Generally, any action which benefits an individual at the expense of others is probably going to be wrong, especially if there's something underhanded in it. This definitely isn't a bulletproof heuristic, but I think it works pretty well. I guess this would qualify as Kantian?