As for getting a cab, we were at the building where you take the skyride to get to Sentosa and we needed a cab back to our hotel, around 5 pm. There was a queue of about 30 people waiting in the cab line. This was especially bad because cabs seemed to be coming at a rate of about once every 10 minutes.
Nearby, near a coke machine, there was a machine that took S$1.50 or so in coins, dialed up the cab dispatch company, and printed you out a receipt. The receipt had a confirmation number on it, and a cab rolled up about 5 minutes later and called out our number! The people in line were TICKED and asked "where is this machine?!".