I have researched this for my FL property. It is state specific. FL law (Bill S 1084 er, 3/10/2020) specifically states that what the tenant needs to provide is per pet and the tenant needs to show:
1) the tenant needs to have a disability
2) what that specific pet does to help with the disability (ie different pet might perform a different emotional support to the owner).
Check to see if your state has the second provision, in which case, you can request a per pet evaluation done by a professional (if your state also clarify who can actually provide this kind of certificate).
In the Florida bill, there is one paragraph that says (line 394 ) "False or fraudulent proof of need for an emotional support animal.—A person who falsifies information or written documentation, or knowingly provides fraudulent information or written documentation, for an emotional support animal under s. 398 760.27, or otherwise knowingly and willfully misrepresents himself or herself, through his or her conduct or through a verbal or written notice, as having a disability or disability related need for an emotional support animal or being otherwise qualified to use an emotional support animal, commits a misdemeanor of the second degree, punishable as provided in s. 775.082 or s. 775.083. In addition, within 6 months after a conviction under this section, a person must perform 30 hours of community service for an organization that serves persons with disabilities or for another entity or organization that the court determines is appropriate." See if your state has anything that specifies the penalty for fraudulently claiming ESA. If there is, I would print the Bill out and highlight the paragraph and have any prospective applicant initial that they read the bill on ESA. This should deter fraudulent claims. Again in this world, those who don't do the right thing always hurt those who do.
On the other hand, if the tenant is a responsible pet owner and takes good care of the dogs and the property (so the dogs don't destroy the property and the place doesn't smell bad), then you have a sticky tenant. But then again, if someone is not being honest, you don't know what else they are lying about.