Yes, especially if they are still serving their NS (National Service) liability stint. Used to be called Reservist Training, until an SAF Scholar and President Scholar, who was a BG, born in the year of the Dragon, by the name of Lee, decided that it should be called National Service instead of Reservist.
National Service was then known only as the 2 year or 2 and half year period which one serves full time. It did not mean the 13 year Reservist cycle or 9 years cycle for some.
Anway, back on track, yes all NS liability pilots in SQ & Silkair (male pilots only) cannot leave the country without any exit permit.
Yes, their (Singaporean NS liability pilots) balls are in the hands of the Govt! And I'm not surprised that the Singapore Govt squeezes them often! But who can complain?