As far as I can see, the BBC source doesn't say anything about prositutes. Why don't you have a look at it?
Zodiac brought up the thing about yellow cards from some other source. A google search will reveal a number of sites quoting the yellow card thing. For example:
http://goasia.about.com/cs/singapore/l/aapic032301a.htm
Oh, and for the love of Christ, learn how to reply to comments properly.