Any emails that you reply to or forward will get trashed re:[EXTERNAL]fwd:[EXTERNAL] etc... Eventually people will disregard the flags because of the noise. It'

Any emails that you reply to or forward will get trashed re:[EXTERNAL]fwd:[EXTERNAL] etc... Eventually people will disregard the flags because of the noise. It's a very narrow circumstance where this would actually prevent fraud. You're looking for someone who would normally wire $BIGDOLLAR without verifying it, yet also pay attention to warning flags which are almost always present. You don't win this battle by trying to block all the possible ways in. Instead you create one approved process for handling $BIGDOLLAR transactions.