Do terrorists use open-source mailservers?

From ABC News:

Attorney-General Robert McClelland says the proposal to let some employers access workers' emails without consent is only being considered as a way to stop cyber terrorist attacks.

...because, of course, terrorists only ever use their employer's mail servers in their nefarious schemes.

Not to be outdone by the government's stupidity today:

"But deputy Opposition leader Julie Bishop says the laws will burden employers"

Yes. It's not like those poor, downtrodden employers have ever been interested in looking at the contents of their employees' email, in the past.