How long has this been the law? I lived in Boston for a while and don't remember this.
I remember it from at least 2014, and wrote about it in 2019: https://www.jefftk.com/p/ma-price-accuracy-law
I remember it from at least 2014, and wrote about it in 2019: https://www.jefftk.com/p/ma-price-accuracy-law