When I think about it, such a claim doesn't even make sense, because for it to be true, all transmission would have to be stopped, instantaneously and completely. But that would be impossible, as there would still be transmission within bubbles, and transmission through all the essential work that continued where social distancing was not an option. That would reset the clock, and since the infectious period was thought to be about 15 days, such a statement could not possibly have been true.
Does anyone have any examples of public health advisories claiming that the lockdown would only last 15 days?