Default value for Radio Buttons, again.

So 8 years ago, the answer was no.  www.joomlapolis.com/forum/developer-members-support/236784-default-value-for-radio-buttons

I realize the new custom field I defined does not have any value set for a Yes/No field, but it's really a basic expectation that I should have Yes or No set by default. 

It doesn't work in the backend field setting to say an empty field is the default.  I can code for the field being empty or zero for the default but is there an *xml file I can edit or JavaScript I can add to a templates file, just to show the default "Yes" is selected in Profile Edit?   An autoaction triggered by Profile Edit seems excessive.

Update: I decided I could accomplish what I wanted with a single checkbox, so nevermind. I'll just leave this up in case any one else is interested.

Technically you can just change the database column default to 1 or 0 if you wanted. The reason 0, 1, and NULL are supported is they're all 3 different states. 0 is explicitly No, 1 is explicitly Yes, and NULL is the user never saved the field. We do allow supplying a default, but only if the field is available during registration. Technically it doesn't need to be visible on registration as you can hide it with CSS. We're avoiding major changes to fields right now because we'll be moving entirely to Joomla fields sometime in CB 3.0 (this will be a feature switch so don't worry!).