I got home this morning and immediately went to run errands. My car in the garage has built up so much dust it is actually brown instead of green in colour. Someone ran his or her finger across the trunk, scrawling Thai. I assumed it was a "Wash me" but the reactions of people around me didn't quite seem to line up.
I finally pulled into the front of my building and beckoned of the girls at the desk to come translate. After a smothered giggle, she read "The car washer has moved abroad."
That would explain why the guards in my work and home compounds were producing belly laughs, but the drivers of passing cars scratching their heads.