Low-health collisions and close-range engagements in general will become more dangerous. One can kamikaze a deshielded opponent this way, which is fün and okay. This will be yet another element of the game mechanics to build one's strategy around.
Not its own. If a cap explodes next to a piece of loot, but they are still too strong for you to come close and pick it up before it does, then that piece of loot will be destroyed. I've just done a mission where I had 3 NPC Dunkirks spawn in the 2nd wave. I killed one, but couldn't get close before I killed another, so the 2nd Kirk's explosion destroyed the 1st's loot. It's cost me $3,300,000.