[NoKnowledge]

FIVE and ITV1 use different satellites to broadcast their regional versions and they've asked Sky to encrypt the broadcast of some of these regions so they're only available to viewers with a valid viewing card. Usually the request to encrypt is because the satellite signal of that region can be widely received outside the UK and Ireland and the broadcaster doesn't own the rights to transmit some programmes to continental Europe. This decision to encrypt channels is down to the individual broadcaster and not Sky.

https://mysky.sky.com/replacecard/