Mama Cass

While an urban legend maintains that Mama Cass Elliot died choking on a chicken bone, her death was actually the result of heart failure.
The public latched on to the idea that Cass died while eating a sandwich, even playing it up to have been a ham sandwich in some variations of the tale.
From this rumor came the joke that, if Mama Cass had given Karen Carpenter the ham sandwich, they'd both be alive today.

Cass died in 1974, at the height of her career, having just finished performing at the London Palladium Theatre.
Cass' heart failure occurred while lying in the same bed, in the same room, where Keith Moon had died four years earlier. The apartment was owned by Harry Nilsson.