I might have walked by the infrared thermometer twice without noticing, but what they do care nowadays is the declaration form. On my mid-July entry at the airport, before getting to the immigration line, everybody squeezes into a hole called the Health Department, which has several people inspecting the form.
HK is now in the community outbreak stage (massive number of confirmed cases with no travel history), so they don't mandate "lockup" anymore (the cliche these days is "voluntary self quarantine").