...is a terrible, horrible idea. Way too may people get fake certificates just so they can bend rules. Meanwhile, people who really need their service dogs are getting harassed and asked for a certificate or license. There's no such thing at this time. All "official", "certificate", "registered" documents are fake. Real service dogs don't have these. They're trained at schools for many months, and they are many levels above all the fake "ESA"s that are flooding the population.