To be fair to them, for a tomato based pasta sauce, I’d bung the tomatoes on with some olive oil for 45 minutes or so to cook down, longer if I was making a large quantity. Which would be a fair chunk of a lesson, even if you can get on with some of the rest at the same time. It kind of depends how much time they have.
And there’s the obvious option of cooking it at home with them and putting it in a jar for anyone who is outraged about bought pasta sauce.
Actually, I bought a jar of pasta sauce the other day for camping, just your basic tomato sauce, dolmio or something similar, and it was surprisingly okay, didn’t have any of that icky preservative that they used to put in that makes it taste metallic and industrial (and makes my wife wheeze, so I always check), and just tasted like a not particularly great but not terrible tomato sauce, was fine for cooking up with some onions and garlic. Nothing like as bad as when I was a student, when it certainly was nowhere near as nice.