I came across this ScriptingHelpers.org question where the OP’s Accessory (Hat 2.0) wasn’t working. It was because he named the part inside the Accessory “Hair” instead of “Handle”. The wiki page kind of mentions it has to be named “Handle” with “If an Attachment is inserted into the Accessory’s Handle…”, but that’s easy to skim over and even if it is read it might not stick out. I suggest changing it to:
“If an Accessory has a child named “Handle”, and that Handle has an Attachment inside of it…”
in order for it to be made clearer that the part has to be named “Handle” or the Accessory won’t work with Attachments.