A quote for you to read...
Sometimes the broadcast network invites you to perform a retune, because there have been transmitter frequency changes or new services added. With firmware 1.02.20 (and previous) a message appears on-screen inviting a retune. With 1.02.27 onwards, the message appears but if you do not cancel it within a few minutes the retune continues without permission (at cost of your recording schedule and the possible need of repeating the retune manually). Call it an opt-out rather than an opt-in. You could be off making a cup of tea, and return to find it in the process of tuning - or even worse return from holiday to find it retuned and no recordings made while you were away*.