just too funny. the MS guys really do think the whole world is MS.
It is funny, and I've had it happen in the past too - I think because of some misconfiguration, not from not using Outlook or Windows. But the idea is that the whole place uses a unified system, which does allow for nifty corporate functions like recalling emails. The issue you saw was that you were allowed to have a rogue setup.
On the other other hand, it is of course very hard to lock down what is by nature supposed to be extremely interoperable