[Bluecortina]

Usually they weren't that simple, they were probably sometimes the most complex junction of the day. Some stations has a routine of multiple slides, captions, live reads, music etc.

However as you say if something doesn't work they could just busk it or skip over it. And of course most closedowns weren't time sensitive, if  Channel 4 closed down at 1:37 rather than 1:36 then that wasn't a problem.

To give some historical input I add the following. In my days involving ITV transmission we were very much concerned with the actual off air time because it involved - money. 

Due to Union/Management agreements in force at the time the actual off-air time was very important, the later it became the more the hourly rates increased - from memory in quarter hour increments. It was a long time ago and without checking I think it started at midnight. So, if you went off air at 00.00 there was no extra pay, if you went off-air at 00.01 staff were paid an additional 15minutes pay at an enhanced rate and so on. I think it went up to a maximum of five times the hourly rate of pay.

Additionally, Union staff were rostered a minimum of 10 hours between the end of one shift and the start of another. If that was ‘broken’ then the second shift started at the same hourly rate as the first shift ended. Union staff could not be re-rostered at a very late stage to avoid this. So, the actual off-air time was very important with some members of staff looking very very closely at the clock at the appropriate time. Not me of course.

Of course as time went by these types of arrangements fell by the wayside.