How do you people use this expression, if you use it at all?

I first heard it used in this sense: "The car rental company wouldn't cover the damage to the emu, so I had to pay for it out of pocket." In this case, it means "out of my own funds" or some such - I bear the cost personally.

I now hear it used differently by people in a particular couple of offices (it seems to have spread among them, and has in fact infected a couple of colleagues here in my office). They use it to mean that they'll be away from the office and thus unavailable, as in "I'll be out of pocket for the second half of June."

A few questions:

Is this totally incorrect usage?
Would I be justified in killing them when they use it this way, or should the punishment be lighter?