I have a 20 year background in enterprise internet security to include email and spam filtering, etc. If that is the conversation you envision my only suggestion would be the typical support one... Please step away from the keyboard. If this truly is a problem then you probably should not be doing what ever it is you are doing.
I hate to break it to you but Gmail is undoubtedly the largest and most well known purveyor of spam, which includes scams, phishing, etc...
Furthermore, users that think they should only trust "Gmail" email addresses are the exact users that will click on the phishing links and submit their personal info.
I have a 20 year background in enterprise internet security to include email and spam filtering, etc. If that is the conversation you envision my only suggestion would be the typical support one... Please step away from the keyboard. If this truly is a problem then you probably should not be doing what ever it is you are doing.
I hate to break it to you but Gmail is undoubtedly the largest and most well known purveyor of spam, which includes scams, phishing, etc...
Furthermore, users that think they should only trust "Gmail" email addresses are the exact users that will click on the phishing links and submit their personal info.