Built4Speed:
So now they often call you before you standby starts, very early in the morning when obviously you should be asleep if working or on standby from 5am.
Yet another exaggeration regarding Ryanair: if your Standby starts at 05:00 then you should be ready to walk out of the door at that time, therefore you will have been awake from roughly 04:15 - 04:30 at the latest to get yourself ready, yes? Now do Ryanair call you at 02:00 or 03:00? No. They simply give you a heads up, to get into the office, at about the time you would have set the alarm clock anyway. To me that's perfectly reasonable & could be even helpful.
To answer the original question, anyone who hasn't been legally prevented from contacting you can call you at anytime, you have the right to have your phone switched off, ignore the call or take the call, whichever you so choose.