Just down the road from us there is a dog training business. It does quite well, I suppose because of all the dogs that people are buying these days.
Or it was doing well until a few weeks since.
The police received a tip off that the business owner was growing cannabis (a false allegation) and raided his premises. What happened next was one of the business owner's former employees who has started a competing business, rang round all his ex-employers customers using their contact details that they had copied whilst in his employ, saying "Do you realise that the police have arrested X for growing cannabis?"
Result, X loses 40-50% of his dogs.
How dirty a trick is that?