> If I were a senior Israeli or Hamas leader I’d avoid the place for a couple of decades in case of sealed charges.

If the Netherlands granted diplomatic immunity to said leaders before their visit, and then decided to arrest them, that by itself would be an act of war.

And even worse, it would ruin basically the only treaty every country has agreed to - the Vienna Convention on Diplomatic Relations.

In practice the Netherlands, by announcing openly they would be arrested before their arrival, had refused to grant them diplomatic immunity. So it is going to be extremely difficult to argue such an arrest would be against the Vienna convention. The Vienna convention explicitly states that the receiving state can declare before arrival that a diplomat will not be granted immunity.