Which of the following is NOT a valid form of prospecting?

The correct answer highlights that competing agents' clients do not represent a valid form of prospecting. Prospecting is the process of identifying and reaching out to potential clients in a manner that is ethical and respectful. Engaging with another agent's clients can lead to conflicts of interest and ethical violations, as it undermines the established relationship between the agent and their client.

In contrast, the other options—social media outreach, networking events, and referral programs—are all legitimate and ethical means of finding new clients. Social media outreach allows agents to connect with a broad audience and showcase their services effectively. Networking events provide opportunities for agents to meet potential clients face-to-face and build relationships. Referral programs incentivize satisfied clients to recommend the services of an agent to their friends and family, fostering trust and credibility.

Therefore, focusing on building one's own client base through ethical means is essential in real estate practice, and competing for another agent's existing clients does not adhere to these principles.