I think almost all operators cancel journeys from time to time, Trent have now decided to let people know about it which is pretty noble of them because as you say it looks bad on them.
There is also a vehicle shortage due to Wellglade suddenly having a PVR increase of 7 when Premiere collapsed, 4 of these from Nottingham and they only got given one extra bus, because other depots are short too. There was also an extra bus on Indigo yesterday because tram works brought Beeston to a standstill, some 15 minute journeys taking an hour.
There are no extra buses or drivers on the Red Arrow. The Red Arrow is run by trent drivers from Derby whereas the above services are run by Barton drivers from Nottingham. They get payed different amounts per hour so it's unlikely they'd send them across.
Red Arrow has quiet journeys but in the evenings when Red Arrow is full, citylink remains very quiet.