The ALC aircraft would not be there if it weren't for EU261. Airlines do not do things unless they make or save money. This setup is for reducing compensation claims.
They've obviously done their sums and have concluded that ALC saves them money. But then again it isn't much different to other locos who have planes and crews on airport standby ready to perform rescue flights lets not kid ourselves that they're doing this to be customer service champions.
The ash cloud was over five years ago. People will have well forgotten and five years is a long time in this industry. They did it then, who's to say they would handle it the same way now?
As mentioned all airlines have good and bad, but reading this thread LS would seem to be the exception. They can only do good seemingly.