Schneier on Security

Roger • November 30, 2009 2:11 PM

“The need and greed principle. Your needs and desires make you vulnerable. Once hustlers know what you really want, they can easily manipulate you.”

And db Cooper wrote: “you can’t cheat an honest person”

While many fascinating scams involving exploiting the mark’s greed, I think the currently widespread claim that it is an essential feature is, itself, a scam to lower contempt for conmen.

I find that most of the really common (and hence little studied) scams do NOT involve exploiting greed, and in fact do involve cheating an honest person. For example, the number one most common scam in my neighbourhood recently works like this:
1. Man dressed in overalls and tool-belt cold-calls a house, usually that of a frail pensioner;
2. Tells pensioner he was doing a job on a house across the road, and whilst working on the roof he noticed a serious problem with the victim’s roof. It needs to be fixed at once as it is a serious safety hazard, but as it is a quick job and he is already in the area, he can do it straight away.
3. “Tradesman” climbs up on roof and bangs around for a bit, doing no actual work, then comes down and demands money from the mark.
4. Repeat a few houses down the street, citing victim no. 1 as the job he was doing when he noticed the next problem.

This scam does not rely on: victim’s greed or dishonesty; distraction; herding; nor social compliance (unless we broaden the term “authority” to mean any kind of trust whatsoever, such as expecting tradesmen to be competent).

It does involve deception, but of a very simple and crude sort: a frail pensioner is unlikely to climb a ladder to their own roof, so they are obligated to accept other people’s reports of problems with it.

The only one of Stajano’s principles employed here is the one which, as Thom noted, was not mentioned above: time. The critical feature of the scam is the time pressure created because the bogus tradesman is able to the job right now before he goes home. Roger Moore notes that this time pressure should often in itself be a warning sign of a hustle; but in this case it arises perfectly naturally, because in many areas it can take a long time to get a real tradesman out to look at a problem.

This combines with the real driver of the scam, which is fear — fear of the unknown, because many people know little or nothing about the basic architectural features of their own private space.

Yet despite having so few features in common with the elaborate “stings” covered by Stajano, this sort of scam is far more common. Don’t get me wrong: I think Stajano’s work is very useful, and in an area that needs a lot of this sort of work. But we do victims a disservice if we pretend that their moral failings are an essential feature of scams. In reality, the essential feature of scams is pure, simple, and often surprisingly crude deception. Everything else is window dressing to impair the victim’s judgement. That impairment can be as elaborate as a “long con” or as simple as too much booze.