Think about NPCs that hire you to kill the person you are escorting. Think about bandits ambushing you, and offering to pay you to let them kill your VIP. And then think of the consequences when the relatives of that person find out what occurred.
all very good plot twists. i'm finding that the possible plot twists are almost endless. i don't think any of the 30-40-50? quest generators planner so far is based around a plot twist. they're all more of less straightforward quests so far. once the various possible types of straightforward quests are well covered, i may go back and make "twisted sister" versions of them. that way you never know if it a straight or twisted quest. ; )
last night i finished up a first cut at both the sacred animals and the escort quest. both are straightforward, but they work. using regular badguys did the trick for the sacred animals quest, although the herd is still just a random animal encounter that might kill both hunters and player alike. making the NPC a follower made the escort quest pretty trivial to code up.
One simple way to deal with applying consequences to escort quests is to simply have a registry / adventure's guild where you pick up the quest. If you're registered as the escort for someone, and that someone fails to arrive, well.. you fail the quest. Be careful of things like on death hooks, because often they don't make sense. For instance there have been times when playing Elder Scrolls games where I've killed someone and was witnessed by someone else, who I then killed, but yet you still get reported.
If you're going to have reporting mechanics, then you should spend the effort to make them work well with the rest of the gameplay. If I exterminate all of the witnesses before they can get to a guard, I should not have a bounty taken out on me, unless somehow my name is registered with regards to the people in question (i.e. I was hired for an escort)