So suppose some alien agency does find the Voyager 1 and 2 space probes and finds the golden record on them. That’s fine enough. And I imagine that they’d be able to work out what the disc was for, since aliens skilled enough to catch a space probe like that probably understand sound waves well enough and can work out what engraved wiggles probably are. And going from a long spiral wiggle to, you know, playing the sound is probably straightforward enough. But what happens if they take that recording of the sounds of Earth and play it backwards? Huh? What then?
Again I’m not saying we have to do something about this right this minute. We can wait until we have some idea what to do about it. I’d just like to know that somebody’s got the problem under control.