One involves arresting foreign passengers on suspicion of stealing from the duty free shop. They are threatened with imprisonment, kept in a nearby hotel and forced to pay a huge 'fine' for their release.
The second scam is this. Arriving passengers, couples and groups presumably, leaving their planes are advised to put their duty free purchases in one bag. After the customs check, they are stopped and their bags opened. They are told that they have too much in duty free goods. The goods are confiscated and they are fined.
This is an evil scam aimed at vulnerable tourists and transit passengers who have no idea about the law in Thailand and no idea where to seek help. It's a disgrace that it has taken foreign news reporters to expose this and force a response from the government. Don't be reassured, by the way, that this will be stopped any time soon.
My advice is that travellers should stay out of the airport shops. If you are bringing in duty free goods from another country, make sure that you are not over the limit and keep your purchases separate from those of other people, even your companion's.
Here's some more information: