I must say that the graffiti was very well done. SMRT would have to pay a lot for it if it were to commission an artist to do it. And I think SMRT quietly told itself that they didn't mind and let the train go around the island with the graffiti on it. But a crime is a crime. Vandalism is vandalism. The culprits must be charged in court and sentenced to 2 weeks jail. They shall serve their jail terms in SMRT depots and made to paint more graffiti officially with SMRT's consent this time. And SMRT can pay that a token of appreciation for a job well done. Put the blame on the Olympic spirit of good sportsmanship since the YOG is in town.