My parents are going to watch my son for two afternoons per week when I go back to work. We are hiring a nanny to cover the remaining three full days and two mornings.

Obviously, we will have to give keys to our condo to my parents. That's fine. But I would prefer that they NOT use their keys if they come for a social visit. I want them to ring the buzzer.

The reason for this is that we are often scrambling to get ready at the last minute when we host. Often we do a lot of last minute cleaning, and then we only have a few minutes to finish getting dressed. And since we live in an apartment with an open floorplan we are not always, uh, presentable, until that last moment.

My parents often arrive early. I just don't want them walking in on us half-dressed with no warning.

Is there a polite way to ask them to only use the key when they are coming to relieve the nanny? Or am I stuck with parents who will be able to barge in at any time?