Hermes does not say on the record that it bans customers but there are theories on social media that you can get banned if you do the following things:
Being caught reselling their products
Hermes really does not like people who resell their products especially their quota bags such as the Birkin, Kelly and Constance. If you are caught reselling instore offers, it is likely that you could be blacklisted from that boutique and the brand. Hermes want loyal clients, not people who are trying to resell.
Being disruptive in the store
This could be a reason of being banned because by being disruptive, you would be putting employees in a difficult position. Being told to leave by security could definitely affect your standing at the store. Being rude and aggressive to employees can also affect your
Getting caught reselling sale items
If you are lucky enough to be invited to a Hermes private sale, don’t resell their items. In the London boutiques, they can track who has sold sales items and some people say you will be banned from shopping from them in the future.