What can be looted can be stole! Or lost. Or taxed. Or have have paperwork attached to it.
Players come out of the dungeon, dragging loads of loot, only to come face to face with an ambush.
The trip to the dungeon was no easy journey, why does the way home have to be? It takes twice as long because of that loot. Some will be lost some will be dumped.
What do you have to declare? What is in the wagon? Loot, you say? Well, sorry to tell you this but that dungeon is on King's land and that means it is his! I am sure you will get a reward for it; 10 coppers on the gold piece is the current rate. Oh, there is also a fine for trespessing, can't have adventures running around thinking they own everything, breaking things, tomb robbing.
Sure, the cleric is fine with his loot, it is all going to the church.