The proper distinction is not between weight and mass. It is between force and mass. Outside the physics classroom, the term "weight" can be ambiguous.Apparently, we exist in a paradigm (the "everyday world') wherein pounds and kilograms are assumed to refer to "weight". Numbers are given units of "lb" or "kg" without distinction. Why that is so is irrelevant to the practical problem solver. It may be incorrect terminology, but we seem to be stuck with the terminology.
Therefore, it seems that the correct answer to the confusion would be in the form of a question to be asked before attempting to solve a problem. It would be something like: "Is that a unit of weight or mass?"
The kilogram is always a unit of mass.
In the physics classroom, "weight" is a force -- the [apparent] local force of gravity on an object. In the grocery store, "weight" is a mass. Products sold by "weight" are officially labelled in units of mass. On the bathroom scales we do not distinguish between force and mass. Whether our "weight" is the 150 pounds force on the scale or whether it is the 150 pounds mass that we pretend that the scale is reporting does not matter. It's 150 either way. In the doctor's office, we'll use a balance scale and get our "weight" measured in pounds mass.
In the physics classroom, the pound is usually treated as a unit of force and is deprecated. In the grocery store, the pound is treated as a unit of mass. It is widely used in this manner in the U.S. When clarity is called for, the terms pound-force and pound-mass can be used for disambiguation.
Out working in the field, we do not distinguish between a stone that requires 100 pounds force to lift and a stone that has a mass of 100 pounds mass. For the practical purposes of the person moving the stone, it just doesn't matter.
Similarly, we do not stress much on whether a 15 pound line will provide 15 pounds force or will suffice to support a 15 pound mass. Or whether a 20 ton jack will provide 20 tons of force or will support a truck with a gross mass of 20 tons.
[If you are selling a truckload of grain at the elevator, you can bet that the scales will be calibrated to pay you for the grain you delivered by the ton mass rather than by the ton force. Though they may dock you for the moisture content]