WebDevStudios/Custom-Metaboxes-and-Fields-for-WordPress — pull request #590 by ebinnion (2014-06-23 16:25:34+00:00)
Title: Adds support for checkbox checked by default

I'd like to suggest this pull request to close #443.

In my testing, the following solution works for single checkboxes as well as checkboxes in repeatable groups.

I attempted to add `'repeatable' => true` to a checkbox to test, but that did not seem to be a valid option for creating repeatable checkboxes.