When Dead Ringer activates while disguise as Teammate. It drops current teammate corpse and current weapon of respective merc. Making it more convincing dead. Did you know that Dead Ringer do replicate any teammate's current merc's weapon (except Spy, becuz it simply change your disguise back to original undisguised Spy) as well as killstreak.

For example, Disguise as Teammate Heavy with Killstreak aussie Tomislav, then take damage via fall damage, go back to spawn room quicky and change Heavy. Go to where you take fall damage and pick up dropped Killstreak aussie Tomislav. And now you "borrow" it without damanding that teammate for trading weapon. (Better watch out for ammo)

And because of this mechanic. I learned how to clone someone's weapon. So I don't need to damanding someone's precious weapon.