As someone who is planning a NOBO through hike with a service dog starting March of 2015, I see a few things I'd like to address in this thread:
First, a prescription is not required to obtain a service dog. While prescriptions are sometimes written, there is no pharmacy where you turn in a script, and get a dog. A *recommendation* from a medical provider (whether a therapist, M.D., etc), is one of many first steps to acquiring a trained service dog.
Second, in regards to service dogs and the National Park System (Federally Regulated):
http://www.nps.gov/policy/serviceanimals.pdf
"After careful review of the issues related to the use of service animals in the national parks, and based on the advice provided by the Solicitor’s Office, we conclude that we are legally required by Section 504 of the Rehabilitation Act to allow all types of service animals into the parks."
"According to DOJ guidance, in most instances we carmot require individuals to show proof of disability nor to show official certification for their service animal."
"If you are not certain that an animal is a service animal, you may ask the person who has the animal if it is a service animal required because of a disability. However, an individual with a disability is not likely to be carrying documentation of his or her medical condition or disability, and such documentation may not be required as a condition for allowing them in the park."
Third, the comments regarding the denying of someone with a disability access to a public facility because of their requisite accommodations (in this case, a trail shelter) is asinine. What isn't outlandish, and this is extremely important, is that the service animal MUST be trained well enough to not show aggression, fear, excessive startle reactions, etc. while being in said public place. We train our dogs *extremely* well, but please remember that in the end, they're just dogs!
And please, don't even think about trying to charge someone with a disability **extra**, because that's totally illegal (
http://www.ada.gov/t3hilght.htm):
"Extra charges may not be imposed on individuals with disabilities to cover the costs of measures necessary to ensure nondiscriminatory treatment, or to cover the costs of measures used as alternatives to barrier removal."