When I worked OB the official limit was 2 but families always questioned why. Always wanted just one more person than we really had room for. So I changed the way I presented it. I said youcan have as many as you want, but they all have to fit on that side of the bed, and once the sterile cover comes off the table no one can leave or enter until the table is removed. And don't touch anything on a green cloth as it is sterile.
That made them police themselves, brought down the # of people to 3 max, and stopped traffic during the actual delivery and recovery period (usually) because they could understand why all those rules were in place. But now that they've redesigned the L&D area the rest of the tribe just waits outside the door and the brave ones sneak the door open "just a little" to see the poor Mom pushing, and we have no one with the time to negotiate with them if the head is just coming out, (or even better a newborn resuscitation).
*******s. I have changed my complete opinion on visiting policies since experiencing L&D, I think it should be a locked unit just to stem the flow of visitors. And what about the people who can't seem to figure out that if the baby was born at 8am that mom must've been in labor all night? No, she had it just in time for everyone to get the chance to visit on the very first day!!