With respect to collecting the 12,000 zuzim (BB daf 77B), if the shaliach was sent by Rav Pappa would not Rav Pappa suffer any loss to the money while it was in the hands of the shaliach? If so, why would the sender be concerned? (I would understand if a messenger was sent to Rav Pappa that the sender would be concerned about the safety of the money until it got to Rav Pappa.)
The Gemara in Bava Kama (104b) writes that if the lender wrote "Hiskabalti," stating that he accepts payment through the Shali'ach, then he would suffer the loss. However, we are afraid that perhaps he died before the Shali'ach actually picked up the money, and his heirs had inherited the loan. In this case, his "Hiskabalti" is not binding on the heirs and if anything happened to the money on the way the borrower would lose.