Also, what are we hoping to achieve with a 7 day isolation for people with colds? Firstly Covid symptoms are different to colds, secondly recent papers show cases she’d virus from 8-37 days!
Time.
At present, if we have community transmission, it will be kept going around the community by people who think they 'just' have a cold, and who feel obliged to man/woman up with paracetamol. By the time they become certain it's more than a cold, they will have spread it to many more people.
If we encourage people to stay at home for seven days, they will either be better at the end of that, or they will not. If they're not, we thank our lucky stars they weren't coughing over everyone over the previous seven days.
Oh, and we'll cut the admissions for complications of colds.