Beware of trying to derive "meaning" from versions of songs found in tradition. They may be confused or altered and will get you nowhere except an almighty tangle. Similarly, texts heard on records or seen in books are potentially misleading if they don't tell you where they came from. Singers ("traditional" or professional) and, often enough, book editors, don't worry too much over whether or not the words make logical sense; and it really doesn't matter.

See, for instance, the recent discussion here that went into interminable and pointless length about whether or not it was possible to kill somebody with a "wee pen knife" and whether or not the term ought to be "weapon knife"; when all the time the words were clearly just a "ballad convention" with no pretense at all to (or undue concern for) strict realism.

That's the case here. It's just a poetic convention, not an anomaly or logical problem. Nobody worries about whether or not it's physically possible (ballads are full of physical impossibilities. So what?)

If you really want to examine "meaning", then you need to look at the earliest available texts. They don't even contain those verses.