I'm old enough to remember the supposed wire that ran up George Bush's back during one of the Bush-Kerry debates in 2004 [0]. Any time a candidate has a poor performance it's easy to create a secret earphone conspiracy theory in order to justify it.

[0]: https://www.cbsnews.com/news/bush-bulge-mystery-unravels/

Surprised they're not spreading conspiracay theory that Trump himself might have been a fake ;-p