I just made an account to respond to this. Shipping scripts is racy and error-prone. It's the wrong approach and is not how any actively developed desktop wants to do things. They want an API they can use from a service, that's what logind provides and that's why it's been adopted. You can also run acpid alongside logind if that's what you prefer, but it will be racy unless you also use logind's inhibitor API.
How so? The canonical solution would be to ship a default `lid_down` script that could take the currently-active policy as set by the GUI as an input. But the nice thing is that adding/tweaking policies is a fully-supported operation, you just edit the script and the GUI config mechanism to support them.