This has gotten out of control in every aspect. A good product speaks for itself, so if Adam's products are really superior to those of its competitors, than it shouldn't matter what an existing Adam's customer explores outside of Adam's products. If a competitive product is really inferior to a comparable item that Adam's offers, than that customer will have learned a lesson and find his/her way back to Adam's.
I feel like Adam's employees openly talking down a competitive product just drives more people away. If you don't want people to buy a specific product, than talk up your own product, don't talk down about the competition. Keep it classy.