When I worked at McDonalds 10 years ago, we had a sttict policy on nugget sauces. One sauce for a six piece nugget, 2 for a nine peice, and 3 for a 20 piece. If extra sauses were needed or you wanted them for you fries, you had to pay $.10 each. As a teenager making minimum wage at the time, I could care less and gave people what they wanted, but would charge when the manager was around. It sounds like the hot mustard falls under this category.

The cost of these individual ketchup packet, for example, is much more expensive than the bulk kethcup that they use when making your sandwich. I think the days of free giant handfuls of ketchup and free sauces are gone as the price of everything is going up. I think most of those ketchup packets ended up in the glove compartment anyway, and eventaully thrown away. Well, except for my grandma who use to have me open up all the extra ketchup, salt, and pepper packets (and of course, sugar) she collected and have me empty them into her bottles and salt shakers at home.

As far as getting the sauce for free because you wanted to "trade" the pickles (or whatever) on your sandwich for hot mustard, that sounds like a nightmare to me. Just image, minus $.03 for the pickle you did not want but add $.04 for the extra onions, and a .0001 discount because your bun was missing some sesame seeds.