Neck massagers are not strangling people, as shown by the case of the Shoulderfles (Shudderflex?):

Let’s all be thankful that the pictured woman enjoying her Shoulderflex isn’t wearing a necklace or much in the way of clothing, and also that her hair is tied neatly atop her head. It turns out that necklaces, clothing, and hair have the potential to turn that peaceful look on her face into something else entirely.
(Credit: Shoulderflex)

No, seriously. One person was strangled to death after her necklace became caught in the personal massager’s rotating component, while another was almost killed when a piece of clothing was caught. Still more have been injured when their hair became entangled in the device.

It’s like Rise of the Planet of the Apes in silicon.