SG visitors permit, legal to leave for a day and then return?

[depends]

I used to do that till my last trip I was caught and given 2 weeks instead of the usual 90 days. Told to go ICA instead. ICA gave me 1 month for the next 2 months before giving me 2 weeks extension on the 3rd visit, as well as No Further Extension that required me to fly out of the country before the end of the 2 weeks. Flew home to Aust and came back to Singapore and got another 90 days.