The gifts of a bad man bring no good with them.

Something given by a person who means you no good is not really a gift, it is an opening. It comes with an expectation attached, and the expectation does not appear until you have already accepted and lost the standing to refuse. This is why the uneasy feeling about a generous offer is worth attending to. You are usually picking up the shape of the obligation before you can name it.

When a favour arrives from someone you do not trust, ask what accepting it entitles them to. If you cannot answer, decline politely and without explanation, and accept that being thought ungrateful is cheaper than being owned.