Heh heh... while I appreciate your sentiment, you probably could have selected a better example. "Sailing" across the sand is probably one of the easier ways to creatively put together a desert warrior and Sailor background just by suggesting the kinds of sand sailing rigs the warrior and their clan could ride across the dunes.
But that does bring up a very good point-- I think there are very few combinations of Background and a backstory a player creates that can't logically be put together in some form or fashion with just simple tweaks to the backstory. So in this case in particular... a player wanted to be from the desert and the game mechanic they wanted was from the Sailor background. Okay, cool. How can we tweak the backstory so as to make them logically work together? So a desert warrior who gets across the oceans of sand on a desert skimmer works great to justify both sides of the equation. Was that the player's original idea for a backstory? Maybe not. But once they decided they wanted Sailor and they decided they wanted to align the two... that simple tweak brings everything together. And quite possibly gives additional depth to the PC that the player hadn't originally thought about (once they start thinking about what these desert vehicles are, why the exist, why their clan uses them, what the clan does with them etc.)
But this of course assumes though that the player WANTS to create a justification between their backstory and a "non-customized" Background from the book they choose. I'm sure there will be plenty of players who won't care at all and will take mechanics just because they want mechanics, story be damned. But that's fine too. And its not like this is specific to 5E24, as that kind of thing happened in 5E14 all the time as well if players wanted specific skills and took a background just so they could get Perception for example.