'You'll Never walk Alone'
First of all, the song is a very strong part of the oral tradition of 'The Kop' singing on the terraces. At times its metre, if nothing else, is severely altered. I doubt very much if the current generation of singers on the terraces have ever heard of 'Rodgers and Hammerstein' or the musical it came from. The genre of terrace chants (IMHO) form a very relevant but autonomous part of oral tradition. They qualify under every single characteristic of 'traditional song' and what's more they are very much alive and being added to constantly. Whether you include the 'anthems' like 'You'll Never walk Alone' in with the chants is a matter for speculation. I certainly do.
You may not like them, but you can't deny they form part of a very strong oral tradition, mostly sung.

Whilst alteration, accidental and deliberate, is an important characteristic of traditional music it is not a requirement. In fact there have been many tradition bearers in the past who have stated the exact opposite, in that a traditional act must be continued in exactly the same way as it was always done, i.e., not being altered.