What is the recommended waiting period for taking your newborn out?

My boyfriend's cousin just had a baby a couple of days ago. I went to see the baby and they were getting ready to take the baby with them over a relative's house. His cousin wasn't there at the time. And I said why are they taking the baby out so early. My boyfriend then stated his mother told him that the baby can go out whenever, but it's the mother that's not supposed to be out. Now correct me if I'm wrong, but I thought it was the other way around. It's a newborn, I wouldn't want my newborn around alot of people, isn't immune system like barely working to fight off anything at this point? I just thought the mother shouldn't do any strenuous activities until after her six weeks?