The confusing thing about the Greek tanker development is that there are clearly other vessels that are closer to the quoted coordinates when looking at up-to-the-minute vessel tracking data.
I imagine this is just one of numerous potential sightings that vessels in the area have been tasked to look at, except someone on this ship, or someone a crew member has spoken to, is a bit more social media savvy or connected to the outside world than your average salty sea dog, and so this particular tasking has landed on some journo's radar.