The matter I think, is the process in which updates are released as final versions for active sites and less to do with if the version breaks.
Testing on a local environment is not a live environment. The components vary so with PHP and the Apache that it is only good practice for developers to test utilizing a real world server hosting environment prior to a final release. Also scripts need to be tested by others.
The impact is unforgiving on production sites when a script has trouble. When things breaks, it all falls on the backs of the site admin and not the plugin developer.
I and many others appreciate the many hours upon hours these developers place to make our lives better as site developers. ThemeMyLogin has become a key plugin for TalkingManuals. In my effort to contribute, I see a need to address a process and offer assistance in testing.
With gratitude,
Ron