It turned out as I predicted in 2015:

Not a single ship has been held accountable for the past three years!
Researchers show that ten percent of shipping companies violate the rules

On January 1st, 2015, the rules for sulfur levels in marine fuels for vessels in the North Sea and the Baltic Sea were sharpened from 1 percent to almost 0.
Relating to this, I wrote that the intention was a good but that it would have no effect, since no one had been appointed to check that the requirement is complied and that no one cheats.
Now the first follow-up shows that not a single ship has held accountable in three years!

In a survey by Chalmers researchers, it appears that every tenth ship violates the rules. In the report, the researchers also show a pattern. Several shipping companies seem to be systematically abusing the system. Ships that rarely travel in the affected areas have more frequent emissions. The same applies to ships that are heading out of the zone where the lower emission levels apply.

"We are in a highly competitive market and these are shipping companies we compete with – of course I'm disappointed to learn that it’s so planned out. This was news to me and very surprising,” vice president of Svensk Sjöfart, Pia Berglund, said to Sweden's Radio.

Despite the foul, not a single vessel has been held accountable for its emissions in Sweden during the three years since the change in regulation. One of the reasons is that today's rules are considered too intricate, and that the people assigned to make sure these rules are obeyed already have numerous other tasks on their plates.

In 2014 the Transport Agency presented a proposal for a type of administrative fee like penalties to more easily punish ships with excess emissions, but still nothing has happened.

This automatically becomes a clear signal to the market; you can violate the regulations without any consequences. Therefore, there is nothing indicating that those ten percent of shipping companies will stop cheating.