
The Microsoft Exchange Team Blog has a two part series on how to disable the Reply To All functionality using MS Exchange. Yikes.
To me, it seems like an organizational disease or culture problem when you have to resort to blocking the feature at the Exchange level.
This function can be disabled at the single user message level with a bit of VBA:
ActiveInspector.CurrentItem.Actions("Reply to All").Enabled = False
(from Redirect Messages)
You can disable the Reply function as well, for "announce only" messages:
ActiveInspector.CurrentItem.Actions("Reply").Enabled = False
And you can even stop messages from being forwarded:
ActiveInspector.CurrentItem.Actions("Forward").Enabled = False
Here's what happens when you try the menu option, press the hotkey combination, or click the toolbar button for any of these three choices:

For ease of use, this code should be assigned to a toolbar, either in Outlook or on an individual message. As far as I can tell, you can not disable these options without programming code.
So save your co-workers from the e-mail storm: if your message does not need a reply, or you want to avoid the Reply To All issue, use these codes to manage your email.





"To me, it seems like an organizational disease or culture problem when you have to resort to blocking the feature at the Exchange level."
To me it seems like a training issue and lack of common sense. It's amazing how often you see it though.
Even from otherwise normal people