Not before you leave a poor review but before you accuse them of being a scammer. They didn't sue for the poor review, they sued for defamation. There's an important difference there.
If I paid a mechanic to put on new tires, but he just rotated my tires instead and said that he had fulfilled his side of the deal - is that not a scam?
This is kind of a surprise to me and why I thought it was worth bringing up. Wouldn't it be nice if this issue was clarified in the BBC article perhaps with some helpful advice about how to deal with poor service or indeed genuine scammers while avoiding being accused of libel.