First, depending on how automated it is, the webmaster might be ordered to keep updating it. So updating the metatag must be a deliberate action and forcing you to update it would be akin to forcing you to lie. Still not clear that they would not do it or try to, though.
Second, in a larger organization the person updating the tag does not need to know whether the data has been compromised or not.
Third, many companies shared data "on a voluntary basis". Whether this is really voluntary or under some thinly veiled threat, there is nothing guaranteeing they won't lie on their own accord.
In conclusion, there is absolutely no way to make "the cloud" safe via tehnical means.