Utensils

Question

The halakhah is that a Jew can't le-chatchilah cook something dairy in a meat pot which is ben yomo. Yet if he did it by accident, or if someone else did it, you can eat the food since it is be-diavad. Let's say someone is cooking me a dairy meal, or even themselves a meal, and I see that they are going to use a meat ben yomo pot, do I have to tell them?