The Covid-19 health restrictions have become so devastating for businesses and tiresome for individuals that even their slightest easing is welcome. From Friday onwards, people can take off their masks while doing outdoor exercise, enjoy a sit-down meal until 9pm and go to the cinema again.But the change must not be mistaken as a hint that it is now time to drop our guard, especially when the government is trying to screen out asymptomatic carriers through a universal testing scheme. Even…