having an ID ticket doesn't help you anyway, because those flights are full and it's hard to travel without firm booking to and from Asia.
Better get one of those cheap tickets and you have your seat for sure. Since Asian people do not earn that much, ticket prices are also fairly lower than in the west. I've travelled to and from SIN more than I wanted and got away with it quite cheaply. Sometimes you get a intercontinental ticket for 600 S$. (that's about 400 US).
If you get into SQ you don't care about ID tickets anymore.
Dani