See my original answer for why I think picking such short messages is necessary. Tl;dr: most people aren’t paying attention and round off details, so you have to communicate with the shortest possible message that can’t be rounded off further in some contexts. Your proposed message will be rounded off to “we don’t know”, which is not a message that seems unlikely to me to inspire the correct actions at this point in time.
See my original answer for why I think picking such short messages is necessary. Tl;dr: most people aren’t paying attention and round off details, so you have to communicate with the shortest possible message that can’t be rounded off further in some contexts. Your proposed message will be rounded off to “we don’t know”, which is not a message that seems unlikely to me to inspire the correct actions at this point in time.