The lesson to learn here is that, as long as Squeeze (or any other Debian suite, FWIW) is not released, there is still a margin of variability in the software it contains. If that margin weren't there, then the suite would have been released in the first place. The point of a freeze, in Debian, is to stop package acceptance in the suite *by default* and undergo a thorough scrutiny of what goes in and what gets out.