Who Bears the Loss?

The answer is: Roomie.  He pays 15 pounds to buy the right from Romeo, but he'll have to pay another 15 pounds to recover the 20--plus, probably, a transaction cost (Romeo is out only 5 pounds net).  But the real puzzle is: how could anyone have been puzzled by this puzzle?   Isn't it obvious?  Or am I speaking now, perhaps, as a commercial lawyer?