"the foreigners asked him to take them to a supermarket for a currency exchange." The foreigners requested the ride to the currency exchange, it's not the taxi driver's fault they didn't have enough Baht. When you ask a taxi driver to take you somewhere, you pay the fare.
I had my bike locked in Bangkok years ago, it cost me 200 Baht to get it unlocked. Even if these brainiacs had to pay 1,000 Baht, it would be a whole lot cheaper and no risk of spending the night in a Thai jail.
I remember someone in Amsterdam telling me that one big reason cannabis is "tolerated," is that pot smokers rarely cause problems. IMO, no one belongs in jail for smoking weed.
Tourists and visitors may not know that pedestrians don't necessarily have the right of way here. The story said he had only been here two days. I often see tourists step out into traffic thinking cars and motorbikes will stop for them...not usually.
Wattie's Beans from NZ are available at Foodland, Villa, Tops, Big C, etc. for about 75-80 Baht. They're very good and offer a lower sodium/ lower sugar version too.