I'm doubtful about points 2 and 3 since it doesn't match my observations of how people really act†, but point 4 really sounds out there. Like, anybody can sue over anything. Does this meaningfully increase your risk? It's really hard to imagine some lawsuit-happy fellow who would sue you if you offered them a refund but not if you didn't offer a refund. Have you actually seen much of this?
† My experience is that people tend to be very lazy about things like mail-in rebates and and money-back guarantees, passing them up even when they're perfectly entitled.
† My experience is that people tend to be very lazy about things like mail-in rebates and and money-back guarantees, passing them up even when they're perfectly entitled.