A player's swing is interfered with by a stake defining out of bounds. The player mistakenly considers the stake an obstruction and he lifts his ball and drops it in the manner prescribed in Rule 24-2b. What is the ruling?
The player incurs a penalty of one stroke under Rule 18-2a and he must replace his ball before playing his next stroke. Otherwise, he loses the hole in match play or he incurs a total penalty of two strokes in stroke play - see penalty statement under Rule 18.