On hole #5 at Cherokee Hills, a player found that his ball had come to rest on a bridge that spans a gulch:
The bridge is classed generally as an Abnormal Course Condition, and specifically as an Immovable Obstruction. The area near the bridge is very poorly marked, but there was at least one red stake nearby. Since we always treat this entire gulch as a red penalty area, we concluded that the bridge itself must be in the penalty area.
Ordinarily, the player would be entitled to free relief under USGA Rule 16.1 Abnormal Course Conditions (Including Immovable Obstructions). However, there is an often-overlooked exception to this rule under 16.1a(2): Relief from interference by an abnormal course condition is allowed under Rule 16.1 only when the ball is anywhere on the course, except in a penalty area. This rule goes on to state that when both the ball and the obstruction are located in a penalty area, the only relief available is under Rule 17 Penalty Areas.
The player wisely decided not to play the ball as it lay, and instead took relief for a ball in a red penalty area under Rule 17.1d(3) Lateral Relief, for a one-stroke penalty.