This option is available for both fixed and variable locks. In case of an emergency and you need to unlock early there is the option to purchase a key (in-app purchase) that can be used once only to unlock and reveal the combination to your phyical lock/safe. If you choose no at this option there will be no way of revealing your combination early if needed in an emergency, even if you purchase a key or have some keys saved.
If you use a key and it turns out to be a fake lock that you’ve just unlocked with it then the key won’t be destroyed and can be used again. Keys will only destroy once it has opened a real lock.
The keys have been priced low enough so that they should be affordable if you need to release early in an emergency.
Keyholders can create locks with emergency keys disabled. It’s not recommended loading a lock where the keys have been disabled, if you’ve no experience with that keyholder.