BMA is Bangkok Metropolitan Administration. The gentleman on the front page is Sukhumband, our governor.

It will be up to your comfort level and language skills to make a judgement call if you are in the situation of being stopped by them. If you are positive you have done nothing wrong you can in theory walk away and they will have a hard time to lawfully detain you. In reality it is not a good idea to stand your ground in a shake-down unless you have connections and / or very good language skills.

But to clarify: I have not seen the BMA scum stop people who didn't litter and extort money from them for the hell of it... But what they do is ignore everyone but foreigners who are littering and to go great lengths to catch you littering.

A 2000 baht littering fine is clearly not for the local market and totally our of proportion. I can run a red light for 300 baht.. 2000 Baht is a week's salary for many people.

Some links to clarify: Archived BKK Post article from 2010

Interesting allegations in a Thai Expat Forum