For some reason guests try to do that. They label children as infants and infants as luggage. I had one guy try to sneak in an infant and I had to explain to him that there was no room for the baby to sleep, the bed was for 2 people and there was no room for a crib. This was clearly stated in the listing’s description and yet they were trying. And if the host is not careful to nip these in the bud, these people would give you a bad review for the room being too small or their stay not pleasant.
https://www.airbnb.com/help/article/433/can-children-travel-on-airbnb Is this the information you were referring to?