Rules Guy: Can you ground your club with a practice swing in a bunker when your ball is outside of it?

The Rules of Golf are tricky! Thankfully, we’ve got the guru. Our Rules Guy knows the book front to back. Got a question? He’s got all the answers.

My ball rolled through a hard-packed fairway bunker and came to rest outside it. I needed to stand in the bunker to play my next shot. Since my ball wasn’t in the bunker, I took a practice swing, hitting the wet sand, which stayed on the clubface. This proved useful, as the sand wound up adding spin to the shot, helping keep it on the green. But is it legal to take a practice swing in a bunker and ground the club? And can you purposely leave sand on the clubface?
—Jim Smith, via email

Be forewarned, Jim: Reading this answer is going to make this the last time you can legally put sand on the clubface.

Rules

The bunker restrictions as set out in Rule 12 only apply when your ball is in a bunker; when your ball is outside it, there’s no issue with going into the sand and making a practice swing, grounding the club or not. (Remember to rake when you’re done, of course.)

That said, Rule 4.1(a)3 prohibits the player from deliberately applying material to the clubface in order to affect its performance characteristics. If you ignore that prohibition and then play a stroke that way, you’ll be disqualified at the first offense. Knowledge isn’t just power, it’s responsibility, too. And, no, you can’t claim never to have read this column!

Got a question about the Rules? Ask the Rules Guy! Send your queries, confusions and comments to rulesguy@golf.com. We promise he won’t throw the book at you.