Courts see people talking on message board as opinions, not facts.
California Appeals Court Upholds Message Board Speech (27 Nov 2001, 4:34 PM CST)
http://www.newsbytes.com/news/01/172455.html
and this is not the only real case.
I don't see any scary reason for not expressing publicly your thoughts. Some people call it freedom of speech, some others don't like this. I guess it depends on which side you belong each time.
Someone can state 100s reasons in order to make someone not to declare his right through the law process. You can do it if you care about him and you think the result will actually hurt him instead of helping him. Or you can do it because deep inside you see through his/her action a threaten, not directly towards to you probably this time, but to your field. Thanks god there are still people ready to risk for their right.