The attached patch introduces a new option for config.ini:

# Offer registration confirmation by email as well as
through the web?
# Default: yes
email_registration_confirmation = yes

When this option is yes, there is no change from
current behaviour. When it is no, then the confirmation
message sent out by the register action contains no
reference to confirmation by email reply - it only
offers web confirmation.

In addition, the option stops mailgw from checking for
email confirmation.