I get that everyone should follow the law, but how would they ever distinguish you from a tourist unless you blogged about it?
But basically as long you work for a foreign company or clients and don't draw attention to yourself I doubt they care too much.
There was a startup founder on HN circa 2017 that blogged about bouncing between Thailand, Indonesia and Singapore.
Working in Singapore on a tourist visa is particularly stupid because they will actually enforce their laws.