In response to a number of queries, I'm finally able to find time to comment on the recent incident off the Israeli coast involving the flotilla of vessels trying to reach Gaza. Specifically, I'd like to point out that under international law, the actions of the Israel Defence Forces (IDF) do not constitute an act of piracy. (See Article 101 the UN Convention On The Law Of The Sea, here.) As EagleSpeak's notes, here, the key part of the Article's wording defines an act of piracy as being one committed for private ends, not one committed by governmental personnel.
That is, the IDF was not intent on seizing the flotilla vessels in order to ransom them, hold the crews hostage, etc. Compare, for example, the actions of international naval forces in the seas off the Horn of Africa, in which vessels have been stopped and boarded in international waters. Sometimes those vessels are seized (and sunk), at other times they are left to continue on their way. Either way, no international laws are being broken either off Somalia or in the eastern Mediterranean. It is important to remember the true definition of acts of piracy and not allow certain individuals to use the terminology to describe this rather bizarre incident.
What is slightly more odd about how events unfolded is the manner with which the IDF decided to carry out the boardings. As others have commented (such as Information Dissemination's lengthy posts, here), the IDF actions seem somewhat stupid in light of previous incidents in which security personnel have engaged in vessel boardings. Putting some commandos on a freighter held by pirates is one thing: A good commander knows the pirates and their hostages will likely be contained within a specific area and there is likely to be ample space on the vessel to effect a safe boarding. But dropping personnel via helicopter onto a heavily populated passenger vessel, at night, no less, virtually invites a confrontation, especially when the passengers aboard said ship are expecting something and are knowingly antagonistic to the idea of being boarded.
In the "what were they thinking?" mode, Information Dissemination posted the following cartoon, which comes from the Center for a New American Security blog (here):