Denying or flagging Airbnb guests who use service animals is discrimination. They are not the same as pets or emotional support animals (both of which you can deny or charge a pet fee for).
I think it is helpful to understand that service dogs are working animals. They go through extensive training to help a person mitigate a disability. Whether it's being their eyes in the case of a seeing eye dog, or picking things up for someone who may not have full use of their arms, a working dog is essentially a tool. As people don't need to disclose that they use a wheelchair or cane, they also don't need to disclose a working dog. There is a lot of misconception about working dogs and as a result, lots of discrimination. This is probably why people with service dogs are hesitant to disclose.
Working dogs, by the way, are expected to be well behaved and well groomed. If they are unruly you can ask them to leave.
When you find out about a service dog there are two questions you can ask that may help weed out the fake animals.
1. Do you need the service animal because of a disability
2. What specific task the service animal has been trained to perform
The following link offers a bit more specific information about Airbnb's policy and common sense exclusions.
https://www.airbnb.com/help/ar...