Kudos to LilFarfa for calling it by the book.
*edit* An ESA at this time does not have any public access rights, nor can be "passed off" as a PSD or a PSDiT. I am a PWD (MI) and the handler of a PSD. As a PSD handler, it is hard enough to go grocery shopping as a LEGIT team with access challenges because the public still carries a stigma and disbelief of MI and how disabling it truly can be. Encouraging people to "train" (whatever that is supposed to me) their ESA's to be well behaved in public is not only a federal offense, but it makes access just that much more difficult for the true PSD teams. There is no formal certification and what you are suggesting is the equivalent of sneaking in your pocket pooch just because he or she is small enough to fit in your purse.
*edit*