knockout/knockout — pull request #1146 by rniemeyer (2014-06-14 03:36:53+00:00)
Title: Make value binding on checkbox or radio input work like checkedValue

It's a common error to include the `value` binding on a checkbox or radio button, often along with the `checked` binding. This error can have strange non-obvious side effects. Hopefully, now that we have the `checkedValue` binding, this error will become less common, but I think we should simply throw an exception instead of continuing with this error condition.