I'd like to take a second to remind folks that this is the reason that companies want to have access to your facebook pages, have you sign away your right to blog in public, etc.

While it's obviously a bit different for a CEO (being more in the public eye, and seen as the 'face' of the company), HR and legal departments are worried about similar backlashes from comments made by 'grunt-level' (or even mid-level) employees.

This is obviously a flawed assumption, because the people at the top of the company have a higher chance of garnering public outrage against a company, yet they are the ones with the most leverage to say 'screw you' to such policies that would limit their free speech and (at least try to) negotiate them out of any contracts.