These would all be details of the agreement. Maybe they set up some kind of fund for these circumstances. Maybe they set some kind of rule allowing the seizing

These would all be details of the agreement. Maybe they set up some kind of fund for these circumstances. Maybe they set some kind of rule allowing the seizing of the vessel, or who knows what. Maybe they go the other route and use their freedom to determine who they do business with, and under what terms, to convince Egypt to sign it. And at the end of the day, obviously this leverage is pretty bad. It seems to be just making things pretty awful for one or a few people, often from poorer nations, where there is no clear and undeniable nation responsible for their predicament. If the 'leverage' is just being left to rot at sea for years on end, is it that useful in the first place?