Syncing in mobileme with 2 devices at the same time

This thought just came to me and I've yet to test it out. I would like to gather some thoughts from you guys first.

Here's the scenario:-

Say I have a mac in the office configured to sync to my mobileme account, and this is tendered by my secretary who is in charged of updating my appointments etc on my ical. I on the other hand has the iphone with me, set up with my mobileme account as well. Let's just say the content currently over at the cloud, mac and iphone is A hypothetically.

Now if the both of us are to update the calendar on the 2 devices simultaneously, lets say I added content B, and she added content C, how would mobileme handle these changes?

Would it reflect content:

1) A+B at the cloud, or :-
2) A+C, or :-
3) A+B+C?

Logically, I would expect mobileme to be able to handle multiple updates to a single account simultaneously. So naturally, I would expect none other than outcome 3 to be the logical conclusion.

Thoughts?