This years SHOT show prohibits CCW.
Pretty standard for all the major shows and events. It is a combination of lawyers and insurance, along with contract agreements with event centers and security. Every industry show I have participated in in Las Vegas has banned carry. It often appears to be an industry thing, but when you read the exhibitor forms you will come across evidence of other issues.
Sadly, we live in a culture where when you reach a certain size you must either accept some things while you continue to fight for the greater good.
Are you aware that not only the NRA, but many other educational organizations, ban carry of firearms in their classes? Some by the students and some by everybody. I haven't dug into them all, but with the NRA it is based off liability - Lawsuits brought by attendees and insurance company rules. And sadly, as instructors we have brought this on ourselves. We have allowed students to shoot each other, shoot us, and we have shot ourselves and our students.
Utopia does not exist, so let's not cannibalize ourselves over little things and destroy our larger efforts.