Throughout history, grave-robbing has been illegal. Yet many adventures feature the party going into some crypt to search for treasure. Why wouldn't this be illegal?
It would be interesting if an adventuring party went back to town, loaded with loot, and were then confronted by the local constabulary. They might be arrested, heavily fined, or just have all their possessions confiscated.In very religious countries, it's likely that they would be executed.
Just something I thought might be an interesting twist for a campaign.