Gifts used as a tactic are unrequested presents that create indebtedness the giver intends to draw on later. The underlying force is the same reciprocity norm Gouldner (1960) described and Cialdini popularized: receiving generates a durable pressure to repay, and that pressure operates even when the gift was never asked for and even when we would rather not owe the giver anything.
Sincere gift-giving is one of the oldest forms of human bonding, so the manipulation hides easily inside ordinary goodwill. It turns malicious when gifting is engineered — bribery dressed as courtesy, grooming that uses presents to build a sense of specialness and debt, or influence-buying where the gift is really a down payment on future compliance. The reliable tells are disproportionality (the gift outsizes the relationship), an unrequested arrival, and strings that surface only after acceptance.
The defense rests on a single correction: a gift confers no obligation. You may accept generosity and still decline a later request, and where the two are linked, the honest move is to decline the gift. In grooming and coercive contexts the escalating-gift pattern is a recognized warning sign — treat outsized, string-laden generosity as information, and seek support resources rather than reasoning about the “debt” alone.