As the title states - how do you disable the customer signup email but still allow customers to send emails into project and create tickets?
All answers above do not answer question.
You must have the "allow anyone can email requests" turned on for any emails to come through. When this is turned on, new customers who email in, STILL receive the sign up option in which WE do not want. How can you turn off the sign up option but retain the "anyone can email".
In short, all we want is the ability to email requests into projects and not have anyone signup for portal access.