Daughter says no visitors for three months

A few weeks ago, my 25 year old daughter told me that she was expecting their first child. She said they weren't going to tell anyone the exact due date, because she thinks her in-laws will just show up around the due date if they know. She also says they will not have any visitors for three months because she wants to bond with the baby. This is not something any of her friends have done. I'm pretty sure she has gotten this idea from the internet. My husband and I have tried very hard to not be intrusive in their lives, not give advice, be helpful. There are some tensions between my daughter and her MIL.

I would like to hear your experiences if you've had a daughter or DIL who has set boundaries like this. As the child got older, did your daughter or DIL continue to add very stringent boundaries about lots of things and/or limit your interaction with your grandchild ? Or did they relax and let you have a close relationship with your grandchild? If they set a lot of boundaries, what kind of boundaries did they set? I'm trying to prepare myself for what is coming and have realistic expectations. And also decide what level of involvement I want to have.