Selecting entries using a checkbox field
Reply via Brandon:

A single field does probably make more sense here, as you have it.

You're close to getting it working, but your syntax for filtering categories based on craft.locale is wrong. Checkboxes fields store the selected option values as JSON, so if you check your craft_content table you will find values like

["option_1","option_2","option_3"]

When you do this:

.regionAvailability(craft.locale)

it is looking for a row where the regionAvailability value is equal to craft.locale. Even if only a single locale is checked, its value would still be ["locale_id"], not just locale_id.

So to fix this just change that parameter to:

.regionAvailability('*"'~craft.locale~'"*')

or

.regionAvailability("*\"#{craft.locale}\"*")

(both do the same thing; just pick the one you think is more clear)