Due to a change to ICANN (global domain governance) regulations, our registrar is expanding reminder emails so that they all include the registrant contact.
Historically, they've provided reminder emails at 60 days, 30 days, 15 days and 2 days to the Billing Contact on your domains, with the 2 days reminder also copied to the Registrant Contact.
From 21st August 2013, they will send all reminder emails to both Billing and Registrant Contact.