Taiwan started restrictions at 00:00 19 March.

A French guy who was staying in TW on visitor visa took a quick trip to Singapore so he could re-enter TW and get another 3 months. He got to TW too late. He left most of his stuff in TW but they would not let him in.

A British guy went from LON-SIN-TPE. His SIN-TPE flight started after the announced time but he originated in LON before the deadline. So, they let him in.