Absolutely, though I reckon the case of the interpreter sending off secrets to the Iranians was a whole level more naughty that getting done for a bit of pillow talk. That was a very serious case.
Things like civillian casualty figures could easily be argued as in the "public interest" so their classified staus is somewhat hooky. Under these days of FoI etc, it's more often a case of having to justify why something should be hidden, rather than simply saying "it's secret, now b*gger off."
The UK population is generally a more cynical one than the US it seems, especially when it comes to stuff like this.
It is a difficult line to tread about what is safe to release and what isn't, but I don't think figures like this are exactly going to surprise anyone. It's a bit like trying to cover up the fact that something big has just blown up when there are already journos on site and relaying the pictures worldwide.