Hello @Nikki43 ,
The request to charge per pet has been around for some time. If you search for "pet fee," you will find lots of ideas and different practices.
There are hosts who allow only one pet because the fee is for one pet. If a guest wants to bring another pet, consider requesting the additional fee through the "request money" option in the reservation. Consider offering some kind of discount for the second pet, such as 25-50%, when requesting the additional fee.
I had a guest who checked in with two dogs. Perhaps due to the long car ride, one of them vomited on the carpet as soon as it entered the house. It was an awkward moment, but the guest and I hurried to clean everything up.