A more thorough explanation:

Definition: Slamming is when a long-distance telephone company takes a customer's service from another company without permission. This can happen through an unauthorized transfer or by tricking the customer into signing a form that looks like something else, such as a form to sign up for a free vacation.

Example: Let's say you have a long-distance phone service with Company A. One day, you receive a call from Company B offering you a better deal. They ask you to sign a form to switch to their service, but the form is actually a transfer authorization disguised as a sweepstakes entry. You sign it without realizing what it is, and suddenly your phone service is with Company B without your permission.

Explanation: This example illustrates how slamming can happen through deceptive practices. Company B tricked the customer into signing a form that they thought was for a sweepstakes entry, but it was actually a transfer authorization. This is illegal and unethical, as the customer did not give permission for their service to be transferred.