@Christine3190 Your concerns are valid and I would say no, that only registered guests are allowed. 3 more people, even if they don't have family dinners, would all be using the amenities you provide- toilet paper, towels, coffee, hot water, etc. And guests tend to take advantage when you are too easygoing. The "just an afternoon visit" turns into them staying for dinner and then, "Well, they had a bit too much to drink (or there was a snowstorm, or whatever) , so it wasn't safe for them to drive so they spent the night".
You don't have to take a total hard line all the time- if you have a nice, respectful guest in residence who asks if their sister could come over for coffee, you can decide that on a case-by-case basis.
A friend who hosts a private suite in her home has a retired couple who book every couple of months to visit their daughter and grandkids. They visit in the daughter's home, but are friendly with another retired couple in town they like to have over some evenings to play cards with. That's fine with my friend- they are repeat guests, quiet, and as the suite is in her home, no one can pull any funny business like they could in an entire place with an off-site host.
And when one of my guests told me she had come to see her grandchildren, I told her if she wanted to bring the kids over sometime, that would be fine with me. She never did, though. But I'm a home share host, so again, no funny businesss can take place.