Aveline
It was never trick or treat when my children now aged 42 and 45 were young. In Scotland we went guising. Guisers had to sing a wee song or recite a poem in order to be rewarded with a little something. There was no nasty trick side of it.
We have never lived in Scotland, but neither dds nor the Gdcs now, have ever performed any unpleasant tricks. In fact when dd1 was still only about 6, I saw a piece she’d written at school about going ‘trickle treating!’ (The teacher had corrected it, I dare say having had a little laugh.)
The Gdcs (now 6, 10, 11) always go T and T-ing locally with a lot of other local children, all dressed up, with a few (often also dressed up) parents in tow. And they all know they have to say thank you very nicely to anyone kind enough to dish out sweets.