It's just possible the spam messages carrying warnings and purporting to come from legitimate sources could actually inspire criminal action. 

There wa a case recently where an e-mail message about people being followed home from Melrose Arch and hijacked was doing the rounds – and then two people were, in fact, followed home from the shopping centre and hijacked.
The fact that the modus operandi of these two crimes co-incided with that described in the e-mail shouldn't be seen to justify spam, as the mail is more likely to have given the criminals the idea in the first place.
"When these e-mails go around, some people could figure this is a good idea – and then it could actually happen," says Petra Kruger, a spokesman for the AA.
The AA is claimed as the source for another spam warning that first appeared about two years ago, but is currently enjoying a resurgence.
This one, using thinly-disguised American English, actually carries an AA logo and is signed by Tom Odaniell (who doesn't work at the AA, if he exists at all).
The neatly laid-out letter warns about a "new hi-jacking scheme".
Kruger says only two people at the AA are authorised to issue press releases and would never issue warnings in this kind of format.