The Office of Fair Trading has many functions of the US Department of Justice, it exists to protect the consumer from anti-competitive or fraudulent behaviour.
On a smaller scale, there are plenty of televsion programmes in which fraudsters and con artists are exposed. Often it's a cross between extortion and theft, so a harsher term than hustler is probably needed. These people exploit victims who are confused and vulnerable.
Typical scam, point to a loose tile on the roof or a damp patch on the wall, warn about tremendous potential damage unless hundreds of pounds of remedial work is performed as soon as possible. The victim is initially scared, but the problem is fixed, the money is paid, and the victim feels better. We see even swifter results if the initial diagnosis was ridiculously overblown or maybe just a simple lie, then no real work at all needs to be done, but the victim can still pay their money and then be reassured that the house is structurally safe (again). The hustler gets his money and the victim feels better. Great?
But those cowboys practise theft and extortion. They should be locked up.
Swap victim's house for victim's health in this story. Would you care for some "alternative" medicine or "complementary" therapy?