When people tell you that more or thicker oil will increase the compression in your engine, most of them would be talking about helping out an engine that had worn out to the point it was losing compression from the worn fit between piston and cylinder wall.

Guys who grew up building hot rods and lusting after muscle cars, back when they first came out, would understand the idea instantly. A lot of them had engines that were losing compression. Thicker oil was supposed to "give it back". It was a common situation at the time. And a strongly held belief by many. But understood by all. Was it an old guy who said that to you?

Nonetheless, the technical discussion was entertaining.