Ideally their notes would have spelled it out beforehand, saying something like:
Kitchen. Day: 2 cooks and 1 dishwasher. Night: 1-in-6 chance of cook preparing for next day.
If they decide in the moment to create a cook there, after the lock has been picked, I'd consider that a failure of GMing.
If the players decide to explore an estate they haven't planned for, and they say, hmm, I'll roll 2-in-6 for each room to see if it's occupied, that's fine.
If they say "I'll make this entrance the kitchen and have a cook there" prior to the players rolling, fine.
The important thing is that they do not create complications which are not directly related to the roll. Because in that case, the player's choice of approach becomes less meaningful as it is less effective at avoiding obstacles.