Royal Mail are going out of their way to deliver in time for Christmas this year; they always do in my experience but especially so right now because of the strikes. I am quite impressed with them.
Then why would they deliberately call their strike days in the run-up to Christmas? Do you think they somehow don't realise that December is always very busy with people posting cards?
If they were striking on some days and then working flat-out on the other days to ensure that all the Christmas stuff was delivered, none of the public would know - so what would be the point of the strike in the first place, other than to convince the bosses that they were apparently 'slacking' normally, if they could strike and still achieve the same level of output?
I think this is going to be the year when a lot of people will just decide not to bother sending cards at all - and then, come next Christmas, the habit will have been broken for good.
Most people now have various (free) electronic methods of instantly conveying their festive wishes; and if there are people you never see, speak to or hear from throughout the whole year and only ever 'stay in touch' out of habit by sending a card that says nothing more than "To the Wilsons, merry Christmas from Lisa, Kevin and family", then seriously what is the point of it all?