I once had the prize of a tournament be a "great keep, situated on the edge of the River Twees, and comprising such-and-such square feet".
The catch? Not only was the square footage inaccurate (the second floor had collapsed), the "border of the river" being much closer than thought (ie, in the great hall), and the whole thing having been uninhabited for 100 years...
It had 10 years of back land tax. Aka, 1000 gold.
My 3rd level party was not pleased.