I get the impression that 'trick or treat' is a relatively recent thing here in Ireland and is an American import.
All Souls Night was still an active custom up to 15-20 years ago, among some older rural people and particularly among Travellers. This was where food and drink (and in some cases cigarettes and newspapers) would be left out for the departed souls.
We were told of this by a Traveller woman , who also told us how she caught one of her children, by then an adult, smoking the cigarettes that had been left out.
When we asked her when the custom had been last practiced, (this was in the 80s) she said, "I'll be putting something out tomorrow night".
Jim Carroll