Yeah, explorers have been doing this for a long time with out much issue at all (as already noted).
What I do is rather excessive though, which is to go a good distance away from the main star(s) of a system, not near any planet paths that I can tell (I don't use orbital lines, as they seem a bit too easy-mode and I don't like them mucking up the view), drop out of supercruise after slowing down my ship, throttle to zero, then turn off all the modules that I can except life support before logging off. I've had no issues with this at all.
It might be a bit overly cautious, but I'd prefer not to have any issues with the game thinking I'm still online, or similar, wasting months worth of exploration data.
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I am curious about logging off on planets though and wouldn't mind more info on the subject. We'll likely find out in the beta either way at least.