Yes, it would be. But, if I were in a pirate-prone region, I would turn the sucker off, and use it receive only. I assume that's what the tanker operators do.
The equipment to do this is called Automatic Identification System (AIS) and it's carried on board the ship. It's not very expensive, depending on the system configuration. The cheapest is receive only, to allow monitoring of nearby ship traffic via VHF signal, a few hundred $. More expensive is the type that transmits your position as well, around $1000 plus the cost of wiring it to your onboard ship nav systems. Then there are the systems that transmit over satellite, and these can run into a few thousand or over.