I,m not sure about crazy but the most practical and effective help I have received on the line is from a couple of fairly new DE 777 Captains who have a lot of previous heavy jet check and training experience.
When I suggested to each of them that they should join the training department they each politely stated almost the same thing. They were happy to pass on their experience on the line to those that wanted it but were not interested in joining the training department. It seems a great waste of talent and experience but I understand their position.
Great guys to fly with too who both run a relaxed but professional flight deck, get on really well with all the flight, cabin and ground crew and will offer to buy a beer on a layover.
Crazy? I wouldn't go that far but I have seen very weird on a few occasions.