In they were in Massachusetts, Minsky might have asked, "Are you here willingly, and how old are you?" And he could have received the reply, "Absolutely, I'm having the time of my life with Jeffrey and all the famous people he introduces me to, and I'm 16."
And the sex might then have seemed consensual and legal to Minsky, because even now in 2019, the age of consent in Massachusetts is 16.