Jumping at shadows, Tom. That link says very little but here's the key:
"The tanker...captain and mate were indicted but not detained for failing to follow safety orders from navigation authorities, the prosecutors said. (Source: AFP)"
If the USCG told you "don't anchor there" and you didn't listen to them, wouldn't you expect to have a problem? All that we know, is that some official instructed the tanker to do or not do something--and the tanker's captain failed to comply.
Ever get a ticket for standing in a no-standing zone? That might be all it is.