I always bring a USGA official with me when I play a solo round.
Story: I couldn't play golf last summer because of torn tendons in my elbow. But my golf buddies continued. One day Chad (name changed to protect the guilty) texted me after his round that he had just shot a 72. He averages 78 to 82, had never shot even par, and always rakes away tricky 3 and 4 footers. I wanted to feel good for him but I couldn't, knowing he did not putt out everything. And when you don't have to make the return putt you can safely charge the hole with your first putt. So poor Chad never got the full enthusiasm I could have, and wanted, to give him.
I know a lot of people that do all those sort of things on the course, but most of them don't keep a handicap or play in direct competition with people who do. Some of my buddies will talk about their scores and I let them. They know deep down that they'd be adding five penalty strokes per round if they played by the rules, but they don't care.
Out of my association guys, who are required to play by the rules of golf, I don't seem much of that. ... Our bigger issue is sandbagging and guys "forgetting" to post their lower scores.