Licensing and exam requirements for tour guides

[Volokh, Eugene]

	The Institute for Justice is challenging Philadelphia's new
requirement (http://webapps.phila.gov/council/attachments/5141.pdf) that
tour guides be licensed and take special history exams.  IJ seems to be
exactly right on this: such a requirement violates the First Amendment,
yes?  I take it that the government couldn't require that authors of
history books or travel books be licensed and take exams; nor can it
require the same as to theaters that present history/geography-related
informational entertainment (except that it could set up content-neutral
licensing requirements for non-content-related reasons, such as making
sure that the theater is properly fire-safe, or for that matter that the
tour guide operator has licensed drivers and adequate accident
insurance).  How could the answer be any different for tours, which are
likewise a form of history-/geography-related infotainment?  Or am I
missing something here?

	(There are, of course, similar requirements for professionals
who provide individualized advice to clients on important matters, such
as law, medicine, psychology, or finance, but here there is no
individualized advice nor the high stakes involved in typical advising
professions.)

	Eugene