PAP government (and many other governments too) have been guilty of restropective application of laws by holding residents hostage. When a resident opens a CPF account (or social security account as known elsewhere), the terms and conditions and regulations as at opening should stay as it is throughout. Any changes in terms and conditions, new regulations and schemes should only apply to accounts opened after the changes are introduced, not compulsorily applied to pre-existing accountholders without their consents, i.e. they should be allowed a choice of opt-in or opt-out.
PAP government does go under the cover of offering certain limited opt-in or opt-out choices, but beneath that cover pushes through and shafts down many no-choices without people noticing, just accepting for granted that's the way law is.