You are saying it's inconceivable that Ahmadinejad would wish to orchestrate an Israeli strike against these ships -- preemptive or otherwise -- for any reason?
Every time the Iranian population rises up and demands change, the Ahmadinejad regime creates a scenario that the west, in some form, threatens Iran....eg: the yellow cake incident, the refining of uranium, and on and on. This distracts the population from home grown issues, and the Ahmadinejad government totters on.....right now there is hope to "throw the beggars out" in the rest of the Arab world, and Iran is on the list. Why, with a little provocation, we can get Israel to liven things up....