On 22 Feb 2002, Stephen J. Turnbull uttered the following:
IIRC it's very inexpensive to have an autoload on a defcustom.
I
believe that triggers copying the form into custom-loads.el, and
generation of an autoload form that causes customize to load
custom-loads if the variable is customized.
You don't even need an autoload on the defcustom for that to happen;
having a defcustom is enough. (And it's custom-load.el ;} )
--
`The classical music makes him feel tranquil and loved so he performs
regularly. What a life for a guy. He gets to make love every day with
an artificial cow.'