Unusual request. In this email, the sender does not want to talk face-to-face or even through a phone call. Be suspicious. Always verify in person or through a phone call using previously known numbers (not one provided in the email) before sending money or sensitive data.
Sense of urgency. The sender creates a sense of urgency in his request and can't even wait till the meeting is over before contacting you. In doing so, the receiver might act quickly without noticing signs that the email is a scam.
You can't stop the senders of these emails, but you can educate yourself and others to recognize these sorts of scams and avoid them. Click the link below for more information from the FBI on online scams and how to protect yourself.