Originally Posted by meesterdowntown

okay...so i did this back in june. i was greeted at the aircraft door by a singapore agent inquiring about my visa. i told him i didn't have one and that i was in transit.
that is when it got weird.
we were met in the terminal by armed security and i was escorted to holding area next to immigration.
a bunch of guys argued with each other as the singapore rep explained my plans.
i was told the flight out could not leave without my reps signature and he would not leave my side.
pretty much everybody took cell phone pictures of my passport and boarding passes.
i just sat smiling and read my book
eventually i was processed through and escorted back to the gate.
security had eyes on me until i boarded the airplane.

so, yes, possible without the visa. if you don't have one, they have to send you back from where you came.
just don't act like an american, be respectful and polite.