Some councils spend millions clearing up illegally dumped rubbish. Why should we pay for the Op's friends mistake at not making sure the person getting rid of her rubbish was licenced?
Normally if someone is offering a service it is up to them to ensure they comply with any relevant laws or licences. Private citizens neither have the knowledge nor the capacity to really assess every single tradesperson they deal with.
The reason councils hold the person who hired them rather than the person that lied / broke the law, is because the person who hired them is more likely to have money and more likely to be afraid of the legal system and thus pay up. The goal is to get money, not ensure justice is done.
