Turn Off Email Address Suggestions

I use my iPad as a kiosk where people can email photos to themselves. After they select an image to be emailed, it attaches the photos into a new message in the Mail app. When they start typing their email address in, it starts suggesting email address that previous users have entered in and they get worried that I'm keeping their email address intentionally to spam them later. Is there a way to turn off the suggested emails? I have no one in my contacts, everyone is in this pseudo-contact state.

Thanks for your help.