I think there’s a name for this sort of thing. Sub-editors putting in a jokey headline, something to amuse the lads, something which they usually remember to correct. I’ve seen reference to it somewhere just over this past few days. This is a nice example of what happens when they don’t remember:

SOME YEARS ago this newspaper accidentally
announced the impending end of the world. With typical understatement,
we did so discreetly. It happened in the Weekend section of a
Saturday edition when a sub-editor working on the church services
column mischievously decided not to insert “Third Sunday before
Advent”, or whatever was supposed to be at the top of the piece, but
“Third Sunday before Armageddon”. The sub meant to switch it back
before the page was printed but forgot. The better part of a million
copies were printed.

In fairness, the readership took it in their collective stride.
Either confident of their futures or worryingly irreligious, this
stunning sentence passed largely without their comment. A few people
did telephone in on the Monday to inquire (a) were we sure? or (b) how
did we know? or, in one or two cases, (c) if so, might it not have been
an idea to put this story on the front page?