You can be mailed into places by having someone else wrap you in a locker, tagging it, and shoving it down disposals. The only downside is that after you arrive, you need to spend 2 minutes breaking open the locker from inside. It's a very easy way to sneak into important places like any of command's personal office. Afterwards, you can jump back down disposals for a quick escape.
Used this method to steal a captain's jetpack completely unnoticed while it was locked down.
Makes for fun assassinations too.
On a related note: Holoparasites can't break/open wrapped lockers. Have fun with that information.
Unfortunately I haven't found a way to mail someone outside of a wrapped locker yet. Jumping into disposals behind a wrapped locker sends both of you to waste, hiding in a second unwrapped locker behind a wrapped one results in the same.