A friend of mine is building a boat. On this boat, he has 12V batteries with a 230V/13A transformer.
Recently somebody suggested he should connect the null with the ground. With DC, this is common practice. But how would somebody suggest doing the same with AC?! Polarity switches continuously on AC.
I suspect he either misunderstood the advice or the advisor didn't understand it himself either.
What might the advisor have wanted to tell? There's no reason to assume malicious intent.