Disclaimer: I know nothing about making addons, so if my idea is ridiculous, go easy on me.
I was thinking, is is possible to make a addon that could accomplish these things, or does one exist already that could be made to do this:
1. Keep a player from going afk
2. Automatically opening an inkeeper, and clicking "Trick or Treat"
3. Detecting a trick or treat bag in inventory, and looting it.
4. And finally, detect the expiration of the Trick or Treat debuff and go back to step 2.
This could greatly increase one's chances at that squashling/hallowed helm since they drop from treat bags now. Dunno if this would be ok with TOS, etc, or if it is even possible, but I'm sure y'all are very knowledgeable about that.