With neither Flash nor ClicktoFlash installed, I experience the autoplaying of those Macworld videos—evidence that the page source code is written to utilize an alternative player if Flash is not present.
I guess I'm viewing your ClicktoFlash case as a subset of the larger Flash not present category, rather than as a special instance of coding to evade blocking efforts by the user, but that's just a hunch based on the fact that online video is increasingly consumed on Flash-free devices.
