A spanking in the butt by the police.
yah, I believe it's 3 strokes of the cane...
coldzero, we're just kidding lah, but there's clearly one line
item in the traffic offences that says "Making an illegal U Turn
when there's no U Turn sign" is a $70 fine.
I don't think there's any automated means of detecting this
(e.g. camera). You'll have to be spotted by the police, who'll
probably stop you on the spot 
