What it does mean that is that the proper recipient of the change does not slip the net, which would then cause a lot of disruption the next day with even shorter notice changes.
Your logic is sound
in the very short term.
If you think a little further and consider the situation as a feedback loop, you come to a different final conclusion........
What this extra tie to Crewing (phoning after end of days work) means is that Crewing can achieve
with even more certainty scheduled departures with aircrew numbers cut to the bone.
Greater certainty, in turn, permits
even fewer aircrew, saving even more cost.
Saving even more cost = even more
lovelee monee in certain people's pockets (and I don't mean the aircrew's, Crewing, Operations or any of the other mugs who seem happy to have their lives ruined).
Lack of certainty in Crewing (someone "slipping the net" as you put it) requires higher aircrew staffing levels in order to provide the necessary buffer. The person who has "slipped the net" has, thereby, secured less disruption and a better life.
OK?