@Kathie61
Consider the insurance implications. Airbnb cover, which is maybe not worth the paper it is written on according to a lot of hosts here, but I had success the one time I claimed, will not be valid for damages or other incidents caused by unregistered people in the listing.
Apart from that, I personally view it as a basic courtesy that people let me know if they are going to have visitors over (that's why I state in my house rules that they need permission). I have a shared listing, where I also live, so maybe this doesn't apply to everyone, but when does one visitor as opposed to 50 and a full on party, become acceptable?
Basically, what I am saying is that you need to know who is going to be in your listing and the guest who books needs to be respectful of that. I am very strict on this matter and guests who violate that rule will definitely hear from me about it.