@funkylab I mean, yeah, if you modified cron to do so. I was assuming that this was adding a random sleep to the start of the cron job itself, which was perhaps a misinterpretation. (I think OpenBSD cron already has this feature, but I’m not sure if it avoids the wake up or only delays the start of the task; and I haven’t seen it in other crons.)
Although of course this might be a premature optimisation, because it hasn’t been shown that there’s a measurable amount of energy being used by cron wakeups in the first place.