Here is a pattern that I'm pretty sure would break it:

if( ... ) {
    # Over-ride default just for now:
    local $hsh{status} = 'backlog';
    $sth->execute();
    ...
}
[download]

Just FYI, as the most mundane thing that occurred to me when trying to think of ways this might break or just surprise someone. delete would also be a no-no (but I found that unlikely to be a 'trap').

Hash values are actually pretty "stable" regarding references to them, as far as I can imagine. :) (But, yes, I'd only use this trick within a fairly small scope.)