Someone dropped a tee in the rough just off the fairway on #11, and my ball came to rest on it. I tried to move it, but there was no way to move it without moving my ball. I thought a tee would be a movable obstruction, as opposed to a loose impediment, but I wasn't certain, so I left it there.
I was right about it being a movable obstruction, because it is artificial. A loose impediment is a natural object.
Rule #15.1 covers Loose Impediments. If the ball moves while you are removing a loose impediment, then it is a one stroke penalty.
Rule #15.2 covers Movable Obstructions. Specifically, Rule #15.2a-2 covers this scenario. If the ball had moved while I was removing the tee, then I simply replace the ball with no penalty.
If my ball was on or in a movable obstruction (think PGA Tour when the ball ends up in a spectator's bag), then you have to drop within one club length (still no penalty). Interesting distinction.
