It is not possible for a customer to 'belong' to multiple affiliates. Therefore, a customer who 'belongs' to a certain affiliate will remain as such regardless of whether they follow any other affiliate's links in future.

The original affiliate will receive any commissions on sales to a customer who they referred originally, even if that customer has followed another affiliate link on subsequent visits.

This is to ensure that affiliates cannot be 'poached' later to deny the original affiliate credit for a customer they referred.