The bike analogy breaks down when a random person comes and surreptitiously takes the bike away from you while you and the seller are arguing. The taker makes n

The bike analogy breaks down when a random person comes and surreptitiously takes the bike away from you while you and the seller are arguing. The taker makes no claim of ownership, they just take the bike and use it, as it is in a good enough condition for them. Who then has the motivation to stop the ostensible theft: you or the seller? The seller doesn't care, but you do. Without possession of the bike you cannot hope to return it in exchange for the money. By contrast, say that a third party somehow manages to make use of Bir Tawil, without having any effect on the surrounding land, without posing as a security threat, and without making any actual claim. Which country is most motivated to intervene in principle: Sudan or Egypt?