SINGAPORE - The spandex-clad duo, fresh off a biking session at East Coast Park, stood at the side of a road puffing on their cigarettes.
One of them casually flicked his spent butt onto the grass, only to be approached by anti-litter crusader Tony Soh.
Caught in the act, the man sheepishly picked up his stub and deposited it in a nearby bin.
Saturday morning, Mr Soh, 47, chief corporate officer of a serviced apartment group, was among about 20 volunteers at the park to pick up trash and catch offenders in the act. Half of them were armed with warrant cards that allow them to take offenders to task.
But three hours later, those warrant cards had not left any pockets: Nobody had had to whip out his card to deal with a defiant litterbug who refused to pick up his trash.
In fact, most picnicking families, joggers and dog-walkers at the crowded park cleared up and binned their rubbish.
Among offenders, the butt-flicker's reaction is typical, said volunteers interviewed, and only one of them has actually used his card since the National Environment Agency began issuing them earlier this year.
That honour goes to Alexandra Health group chief Liak Teng Lit, who helms the latest effort to keep Singapore clean.
Although he has warned more than 30 people for littering over the last few months, he took down the particulars of only one man he caught smoking in a non-smoking zone and throwing his butt there. The information went to the authorities and the man was fined for littering.
"He gave me his identity card and didn't make a fuss," said Mr Liak.
"On another occasion, there was a man who screamed at me in Hokkkien, saying he'd just been released from prison after 10 years and wouldn't mind going in for another 10. But even he calmed down eventually and picked his tissue paper up.
"On the whole though, once you approach them, they respond quickly and apologetically."
This is particularly so when litterbugs are reminded that they are lucky to get away with a warning rather than a fine, said volunteers.
Under the law, litterbugs face a composition fine of up to $300.