>> how likely it is for someone who has been vaccinated to be contagious
again, preliminary results show that you are right. But opposite thinking goes as following: vaccine may prevent serious illness more than viral load. Then, vaccinated person will be walking around feeling healthy but possibly infect others, especially those with whom they are in prolonged contact, such as family. Just like children …
Even if the load reduction is confirmed, the question is – by how much. Would it be enough not to reduce other measures. And the main protection, of course – despite the threads online – is not the masks, but deciding where not to go.