They have already send e-mail notifications (good for them and for us), about B2X. I guess it's the same with Segwit2x.
If they don't list/add some extra coins,stable and with good volume they will be behind from all the other exchangers.
I am not saying that you (as an exchanger) have to have them all (coins,tokens etc) but you have to have more than three and expand.
Of course i totally agree with this, that's the main purpose after all...
Whatever will be most profitable for them.