I'm not sure an ignore button would be a good idea (but then, I'm kinda amish when it comes to buttons).  I fear that when people can visually ignore someone, egos will get bruised and some people might start bickering about "why someone pushed it when they were making a perfectly valid point" or "why someones always ignores some people but not other people".  Then there are those who'd get hurt and just start pushing the button for everything.  If you want a button, give the admins an "I'm calling Chuick Norris" button.  That should settle people down.

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