Well, you could go through the Blacklist and when you find words the Admin's like to use, simply click on the little green tick. It allows those words.

Might be a bit labor intensive but should work.

There is a really cool core improvement for this issue available at http://forums.b2evolution.net/viewtopic.php?p=87955#87955 and do notice that the post after that one identifies an improvement to the improvement. And actually you might want to go up to the top of that thread because first you have to try to turn off antispam blocking for the admin group, then notice it doesn't work, then improve a core file.