A warning alert such as the following will be added to the message body automatically if the impersonation is in our protected VIPs so that recipients can be alerted on the impersonated message:

From: John Ching <professormail234@gmail.com>
Subject: Available?

professormail423@gmail.com appears similar to someone who previously sent you email, but may not be that 
person. Learn why this could be a risk
...........

In case the impersonation in not in our protected VIPs, the following warning alert will be added upon user complaints:

From: Jack Ng <professormail123@gmail.com>
Subject: Available?

[ALERT] : The sender of this email may not be affiliated with HKUST. Be cautious!
...........

Users can just delete such impersonated messages and no need to take any action.