Presumably so that Chase doesn’t have to pay for two lounge experiences (I have done dinner at Davio’s then drinks in the lounge in the past with two guests, so I am definitely part of the problem there).
I did not test it. It also makes me wonder if the other Priority Pass outlets (Stephanie’s, the AF lounge, and The Club) are similarly limited.
This is the first I've heard of a restriction along this line. Flying through Boston over the weekend and debating whether to test it. Not sure if they would let me in with my Amex Plat PP annual visit if they initially reject my Chase PP...