Why didn't you just say this in the first place?
When handicap reporting is off and it's in the off season, no one cares. Use a handwarmer if you want. You'll still be dealing with mud, plugged lies, casual water, wind, drizzle, temporary greens, and other slop that will overpower your heated golf balls. If you want to play in sub 45 degree weather more power to you.
When I look at Spieth I can't help but think of David Duval. For that reason, who knows if Jordan comes back.
I did find this article from a couple of years ago...
Okay, here's another Garmin related one. I have a Garmin G80 with a launch monitor. I could drop it on the ground about 1 foot away from the ball. It will measure estimated carry distance, swing tempo, and smash factor, swing speed... blah blah blah. Say I just want to check my swing tempo because something doesn't feel right. It won't emit a beep or anything that will aid me. I just make my shot as normal. Would using it that way be legal in any round other than a round with "Muppet rules" that doesn't get reported.