Love the idea. I am still surprised that so many ships travel through that area without reasonable protection. Compared to loosing a boat or crew, hiring a few mercenaries with guns and RPG's seems pretty easy for a big ship and shipping company. I am not advocating violence, and am not a "gun freak" but this is not a reasonable, rational group of people with a long history of civility we are talking about. A few RPG's up the "bow" would make them think a little more closely about their livelihood....In order to suck in as many of these scum as possible, ships should each secretly have on board, a small military unit (from each flag country) in disguise (or a paramilitary unit.)
So, the pirates don't get scared off and hide from blatant military ships/teams; their intentions are clear in coming up to a ship; and the military doesn't have to hunt down essentially, civilians (who can hide amongst non-pirates fairly easily).
When approached and intentions are clear, these hidden units can defend with prejudice.
This would do a couple things...quickly weed out a number of these pirates, and act as a deterrent.