CBField for Email Verification

Hi Unfortunately we have a small number of subscribers who dont have valid email addresses - we are a rural landcare organisation - we assign username@foo.foo to these people
Its important that we can distinguish people with these emails addresses in CB Lists displayed from the front end
This is currently done manually by assigning a value (1 or 0) to a required cb field called cb_validemail at registration/subscription
For most subscribers this is an unnecessary field and one potentially redundant step in the registration process for most but made necessary by the non email people. Is there a potential solution to this with CB Fields in CB Subs? ie the valid email bit be set in this field when (most) people who are registering have their email address confirmed?
My platform is cb 2.0.15+build.2016.12.02.00.46.33.ef62bd55e and cbsubs 4.1
Any advice appreciated
regards
Tony Marsh

You want that field to be marked automatically after subscribing or after they confirm their email? If after subscribing you can use CBSubs Fields to set the field after plan activation. After confirmation would require CB Auto Actions.