It won't get me in trouble for manipulating. But you misestimate what's going on: Such a strategy isn't manipulation-minimizing. In fact it depends on some (positive) manipulation, trying to frame the question in a way that makes the other person more comfortable saying no. There's also some negative manipulation going on, however, in that the framing -also- makes the other person less likely to say no, even if it is just at the marginal cases.

Effective manipulation doesn't rely on changing another person's thought processes, it relies on subverting them. Don't make them into a person who will do X, be the person they would do X for/to.