Takes all kinds, @Dawn162. My guests have never done that so far, even though they have full use of my kitchen. One approach to mitigate this might be to have a designated shelf or drawer in the kitchen for guests, and a section of the fridge that you point out to them when they arrive. "So this drawer is yours to keep any dry goods you might have or buy, and this section of the fridge is for your food items" kind of thing. Hopefully they'd get the hint.
I also tell my guests (none of whom usually stay for more than a week-10 days) that they are welcome to use my bottle of cooking oil and the salt and pepper as I can see where they might not want to have to buy a whole bottle of oil or bag of salt for a few meals.