Pay for lighting to play

We stayed at a place in Cha Am. The selection of that hotel was based on having a bathtub and a pool or snooker table for the boy. Snooker room was fine, table good. So we started to play. Being dark we looked for the light switch. There it is I said. But wait. There’s a sign and a box resembling a vending machine. Sign said ฿10 for 6 minutes. Maybe not too uncommon for paying to book a table but being told it’s free to play then finding out about paying for light seems sneaky. Luckily we didn’t have pay for using the lights in the room!