What practice involves contacting customers without the knowledge of the primary salesperson?

Backdoor selling refers to the practice where a salesperson contacts a customer without the knowledge or consent of the primary salesperson assigned to that account. This approach often undermines the relationship between the primary salesperson and the customer, as it can create distrust and conflict. It's considered unprofessional and can damage reputations within the industry, as it disrupts established relationships and may lead to ethical concerns regarding business practices.

This practice is often frowned upon because it bypasses the trust and rapport that the primary salesperson has built with the customer. In contrast, the other concepts presented do not accurately capture this behavior: secret selling and front-end selling do not address the aspect of undermining or operating behind someone's back, and ethical selling emphasizes building genuine and respectful relationships with customers. Thus, backdoor selling is the term that correctly identifies this practice.