The Changi airport check in for 2P is with the rest of the general member boarding. That has been in effect for over a year now. Only F & C passengers along with UGS & 1K are allowed to check in the business & first class lines.

On a side note, I remember when this was instituted and was standing in line with this obnoxious guy with his Chinese wife. After cutting in front of me he was asked for his BP which showed he was in Y and he tried to get into the biz line since he was 2P - the security guard told him he was in the wrong line and had to go to the other 5x longer line. He tried to intimidate the poor guard but to his credit, he stood fast. Since I was next he said what about him, how come he could use this line, he's also only a 2P but the guard just shot back and said yes, he's 2P but he's travelling in C! ^