This is, I think, a valuable heuristic. Anything but the most complex and long-term scam always includes some call to action, nearly always URGENT and IMMEDIATE

This is, I think, a valuable heuristic. Anything but the most complex and long-term scam always includes some call to action, nearly always URGENT and IMMEDIATE (so as not to give you a chance to think about it or research it). A notification that is ONLY a notification about something is very unlikely to be malicious (though could certainly be erroneous). My bank will send me a concerning email or SMS about suspicious activity that needs to be reviewed or confirmed, but because they know it's a vector for attack their specifically ask you to call them at their published number listed on your card.