On Wikipedia's website... http://en.wikipedia.org/wiki/Wi-Fi
Under the heading... Origin and meaning of the term 'Wi-Fi'
It is stated... The Wi-Fi Alliance themselves invoked the term 'Wireless Fidelity' with the marketing of a tag line, "The Standard for Wireless Fidelity," but later removed the tag from their marketing. The Wi-Fi Alliance now seems to discourage propagation of the notion that 'Wi-Fi' stands for 'Wireless Fidelity', but it has been referred to as such by the Wi-Fi Alliance in White Papers currently held in their knowledge base:
"... a promising market for wireless fidelity (Wi-Fi) network equipment." 
With that in mind, this Etymology should not state "Some wrongly believe that Fi refers to Fidelity as in Hi-Fi" It seems to contradict the Wikipedia Origin. Or at the least that it's not clear and this page should not use the term "wrongly believe".