The advice from Chris Whitty could not be clearer.
"You cannot in an epidemic just take your own risk. Unfortunately, you're taking a risk on behalf of everyone else."
Sadly there was nowhere near enough evidence that the UK Chief Medical Officer's words were being heeded in Belfast and beyond on Monday.
The most obvious sign of compliance is the wearing of face coverings in shops.
A snap survey by the Belfast Telegraph in the so-called 'big three' supermarkets in Northern Ireland suggested that the majority of people are still following the advice.
There remain, however, a significant number who simply are not.
During a tour of half-a-dozen stores in some major shopping areas across the city it was not hard to spot the culprits.
Obviously there are some, who for medical reasons, are not wearing face masks, and no one has an issue with that.
But when you see a man walking towards you with a black mask dangling from one ear, or a woman with a covering placed around her chin, nowhere near her mouth and nose, alarm bells ring.
It is ironic that these offenders possess face coverings yet chose not to use them where they are most needed, especially when wearing them became compulsory six weeks ago on August 10.
In Sainsbury's at Holywood Exchange at 12.30pm, just two people out of at least 100 appeared to be without face coverings in the store, which was doing a fairly brisk lunchtime trade. Most of the staff also seemed to be covered up.
Over at Tesco Knocknagoney some 14 shoppers had no face coverings, and one woman was wearing hers on the nape of her neck. It was 1pm and a couple of hundred people were in the store, so not a bad result considering.
Masks were being worn by the majority of visitors to Asda Living at Cityside, with a mere three people out of 30 not complying.
Just around the corner at Tesco in York Gate, however, and the situation deteriorated dramatically.
At least 35 people were not wearing face masks in the supermarket at a time when it was not overly busy and there were probably less than 100 people inside. Two women, carrying their shopping, ambled out together chatting, face masks around their necks. Outside, in the small mall area in front of the store, numerous people were unmasked.
At 2pm at Asda in north Belfast a couple of hundred people were in the store. Only 18 were not wearing face masks, including several young mums with children in buggies. During a visit to the toilets it was hard not to notice that a woman, who was wearing a mask, left without washing her hands.
Last stop, Sainsbury's at the Kennedy Centre, produced similar results.
At 3pm the superstore was not overly busy and around 20 people out of just over 100 weren't wearing masks. A group of four had also removed theirs for the purposes of a lengthy conversation. But most worrying of all was the area inside the centre. Few people were covered up as face masks were being worn on one ear, on necks, chins and foreheads.
It makes grim reading when chief scientific adviser Ian Young said today that we are now averaging well over 100 new cases per day, with the percentage of positive tests also increasing and the R-rate currently at 1.4, although it stands at 2 in some places.
And, as Professor Whitty warned, we are in for restrictions for at least another six months.
Those statistics are a stark reminder that the decision to wear a face mask is not just about you.
Your actions have consequences.