Here's an idea, change the HIIPA laws to allow common carriers to require proof of the disorder and that the animal is certified in that field. If there is an allergen alleged, then allow the common carrier to require that the allergen is a life threatening allergy and require that passenger to carry an antidote such as an epi-pen.
And also the ADA regulations with regard to proof and what can and can not be asked. Sadly, once any law is enacted and the entitlements begin, good luck on ever changing it.
I have know a mid-30's who had multiple Service/Seizure Alert dogs. They can only work so long and have to be retired and not all make it, even after extensive training. The training these dogs go through and the expense and training the family go through is substantial but they did it the right way and through an organization.
We have been around true service dogs many times, unless they are actually working, you hardly know they are there. At a restaurant the dog will lay under the table at the handlers feet and most never know the dog is there unless they see it walk in. Contrast that with the untrained (for true service dog work) family pet and that someone turns into a "service dog" and it is pretty easy to spot the fakes.
Nowadays someone can buy a "service dog" kit on the internet and due to the restriction of what can or can't be be asked, the untrained family pet gets the owners the benefits that come with a true service dog.
