After spending several months developing a good relationship with a business client, rob's client is now purchasing substantial amounts of products from rob's company, resulting in high commissions for him. after checking the sales records for the past six months, a colleague of rob's started visiting the same client in the hopes of capturing some of that client's business too. although he considers it "legal and fair game," sales reps in his firm have begun to avoid him because they consider it a violation of what ?