I'm sure the reference to no charges is well meant but in reality it is extremely stressful for many hosts. That's because it acts as inadvertent open-door invitation for guests to bring along more than they booked for!
According to my own private 'survey' of friends, acquaintances, almost all of them thought it meant exactly that.
Book an apartment and invite as many as fit because "hey, we brought along a ton of air mattrasses or we'll all pile into the 2 available beds!"
Almost every time I react to somebody on the community complaining of dishonest guests they had that setting on their listing.
There used to be a way to trick the software into having that setting disappear completely, but it doesn't work anymore.
I suggest the statement could be: "Extra Guests: No exceeding maximum number guests"
or "Extra Guests: Contact host" or simply have the option to leave it out completely.