I'm suspicious of the wording "court-appointed estate administrators" who might not be working in the interests of the heirs. They might troll through e-mail accounts searching for words such as "download" (it takes only a second to go through years of e-mail) and counting on earning a commission from a rights-holder or rights-holders shell companies for some sort of out-of-court settlement against the deceased's estate. Illegal? If you can imagine a lawyer doing something, some lawyer has done it. I'd be more favourably inclined if the estate itself or the main heir were to have the access to the account.
I wonder why this is an issue only for Yahoo and not for other e-mail purveyors.
Finally, for other oldsters, do you remember Usenet groups? And how so many groups had FAQs? Every month an updated FAQ would be posted. I noticed in one group that the FAQ was continuing to get posted, but did not contain new info. It was not difficult to find out that the FAQ poster had in fact died more than a year earlier, and that his auto-mailer was continuing to send out the latest FAQ every month. A peculiar legacy.