Well, the US military is not above blowing up other people's pipelines, among their other crimes and outrages, so I suppose if they're going to start sinking tankers, then that's what they're going to do.

Plus, if some tanker carrying Russian crude with western insurance had an "accident" of any type, would the insurer ever be allowed to pay out? I think that's the last thing that would happen. They've already proven they're not above swiping yachts because of the well-known crime "rich and Russian".