Spoiler : Episode 2.17 - Extended Promo 

No, no, no Chuck! What are you doing?

omg....

OMG!
Chuck what are you doing?!!!!
And what?!!!! "She was the most beautiful woman I have ever seen!"
That should be about Blair!!
ANd OMG Dan! No!!!!!!!!!! What are you doing!?
I hope Blair and Serena kill that bitch!

wtf chuck?!!! and how can blair be expelled!!!! omgggggg

*speechless*
omg, omg, omg...

OMFG, Chuck! Blair is your one and only, WTF are you doing?

And they can't expel Blair for something she did outside of school. Nor can they expel her without proof.

(Although I must admit, I've been waiting for quite some time for Constance to do something influenced by Gossip Girl. I mean, how could they not know?)