If you loose your hardware, you cannot be distinguished from people who don't have the right Sesame card. The whole idea of Sesame is to verify if you possess a piece of hardware, so loosing it is a real problem.

It is possible to arrange a backup. All you do is order an additional card, and register it for purposes of backup. This means that you still need to enter a single confirmation code, but that you may use either card to enter it.

Be sure to store the second card in another place than the first one, to avoid loosing them together. You may want to lock the backup card in a vault, or hand it over to someone else.

Note that all cards registered under an account are equivalent. A person holding one card is able to do the same things as another person holding the other card.