This is not true. There are various valid reasons for leaving Scotland or your council area.
As for Boris, he probably should not have travelled so he could maintain the highground over hypocrite Sturgeon, however he did. He was clearly on official government business, so is clearly working. Remember, the policy of the government of the United Kingdom is to maintain the union, therefore is he is campaigning for the union, it is official government work. The Scottish Government likes to use this line frequently when using government time/money for promoting independence. From what I saw, he visiting a UK testing lab and observed the UK armed forces assisting with the vaccine effort. In addition, as the Scottish government is currently screwing up the vaccine distribution, you could probably argue the Prime Minister of the United Kingdom has a valid reason to be on the ground finding out why.