I think that the foods that they get the participants to try are split between ones that are genuinely intended to get them to try something they might like, and things the producers are pretty sure they won't like, but bung in there because it is good TV.
Jamie Oliver was the same with his programme about changing school dinners - some of the dishes he introduced were too far away from what the kids were used to, and there was little chance they were going to like them, whereas if he had made healthier versions of the things they did like, there was a much better chance of them liking the new foods.
@Graphista - I use the scone recipe from the Penguin cookbook -
8 oz self raising flour
1tsp salt (I don't always bother with this if I use salted butter)
1-2oz butter or margarine (I use butter, and generally only 1oz)
Approx quarter pint milk.
Rub in the fat to the flour - you can do this with a quick blitz in the food processor.
Quickly add the liquid and mix in using a knife. Toss the mixture lightly. Add enough to make a soft dough.
Pat the dough out gently - don't knead it or over work it.
Cut out, brush the top with beaten egg or milk, and bake in a hot oven (180 degrees/gas mark 7-8) for 10-12 minutes.
For sweet scones, add 1oz of sugar to the flour before you rub in the fat. Add dried fruit - sultanas for example, or glace cherries - after rubbing in the fat. When I make cherry scones, I glaze the top with egg or milk, and then sprinkle on demerara sugar.
For cheese scones, add grated cheddar after rubbing in the fat. The recipe says 2oz - I add a lot more than that - the scones tend to slump somewhat because they lack structural integrity, but they taste delicious. I also add wholegrain mustard with the milk. I sprinkle some cheddar on top after glazing.