Usually when I give a person or organisation a disposable email with the domain or sender keyword, I will go in after the first email and set it up so that 5 or 10 emails can come from other domains or addresses in the case the person or organisation emails me from somewhere else or even that they are changing their address. If I receive spam later I adjust accordingly so that it becomes more exclusive (like in the case of overstock.com when I began receiving spam).
I would like to see a feature that allows the user to set things up so that when spamgourmet receives an email with the sender or domain keyword for the first time, it automatically sets up the email address to allow a certain number of emails from elsewhere. This would also be useful for when a person gives a domain or sender keyword for an email in a form and an automatic email is sent out to confirm from one domain and then regular emails appear from another - you wouldn't lose the emails.
Regards,
Ben