Thaivisa has another warning out on the 'shoplifting' scam run by the staff at King Power Duty Free at Bangkok Airport:

This one's been running for a while.

Basically, there are some notional (& invisible) lines in the King Power shop, supposedly separating one section from another.

If you pick up an item from the shelves & carry it over one of these invisible lines, they pounce on you & say you have been caught shoplifting.

You are instantly presented with a declaration of guilt which they demand you sign.

You are scared, you are about to miss your flight (perhaps on a non-refundable ticket)...you sign. Then you pay their "security department" a large amount of money to drop charges.

Then they let you go.

Golden rule at Thai airports: do not enter King Power Duty Free shops.