I have a habit of knocking and ringing the doorbell none-stop. Funny to a point. However I did this once at a friends house with a newborn.
I think when the 3rd nail was being hammered in to my open palm and I was being raised from the ground did it vaguely dawn on me how stressed a newborn can make you to outside noise and intrusion.
Make rules. Explain why beforehand. We had two friends staying weekend before last -jeesus they were noisy (normal) but to us it was grating.
It seems unfair to non-parents and can come across as though you are suffering them but you need to explain clearly why first- 'look we are worn out and really would like to see you but you cant stay til Midnight holing the baby Grandma'.