The most direct and recommended feature to prevent specific customers from initiating future chat sessions is by creating an IP blocking rule. When a service agent identifies a customer using abusive language, their IP address can be captured from the chat transcript. An administrator can then add this IP address to a blocking rule in the Chat setup. This action explicitly prevents any future chat requests originating from that IP address, directly addressing the requirement to block abusive customers from starting new sessions.

A. Create sensitive data rules: These rules are designed to automatically find and mask sensitive information (like credit card numbers) within a conversation, not to block a user from starting one.

B. Enable Assistance Flag Configuration setting: This feature allows an agent to request real-time help from a supervisor during a difficult chat session. It does not provide any mechanism for blocking the customer.

1. Salesforce Help - Block Visitors from Chatting with Agents: "Create rules to block visitors from specific IP addresses from chatting with your agents. For example, you can block visitors who send spam or abusive messages." This document explicitly states that IP blocking is the intended feature for handling abusive users.

2. Salesforce Help - Create Sensitive Data Rules: "Create sensitive data rules to find and take action on sensitive data in customer conversations... For example, you can create a rule that finds a credit card number pattern and either deletes the message or masks the number." This confirms that sensitive data rules are for content filtering, not user blocking.

3. Salesforce Help - Raise a Flag for Supervisor Assistance in the Console: "Agents can raise a flag on a chat or messaging session to get a supervisor’s attention. For example, they can request help with a difficult customer or a question they can’t answer." This source clarifies that assistance flags are for agent support, not customer management.