I remember in 2003 reading that they were a bit worried that the Gulf War would begin on Red Nose Day and cause chaos with the schedules that night, though happily they held off for a few days. Of course the Paris attacks happened during Children in Need the year before last and some people on Twitter suggested they should have abandoned it, but that was never going to happen, nor should it have.
I recall the start of the War on Terror was a rare occasion of presumably 'network recall' being used on ITV, as it started Sunday teatime during regional variations, I recall Yorkshire's Soccer Sunday (which was a live programme at that point) was recalled and wrapped up as they crossed to ITN.
Also I remember that ITV's new live daily quiz show The Biggest Game in Town was slightly disrupted up by 9/11, as the questions were supposed to be about the days news, but obviously there was no other news after 9/11 that was light enough to put in a quiz show, so they had to just use normal questions.
Obviously The Queen will be of all together different proportion to what we've seen in recent years, but other than that, schedule changes do depend on what is in the schedule in the first place. Even at the BBC I bet decisions are made with one eye on this which they would never admit. Sometimes channels get praised or slammed for the speed they put out extra news bulletins or obituaries, but often it will depend on what was in the schedule in the first place, which leads to inconsistencies. The Doctor Who example is one of these.