We have a lot of forms where we perform lookups and need to automatically select radio button options or checkboxes based on the lookup result. The way we currently handle it is via a fair amount of JavaScript that serializes/unserializes the user's choices and stores the values in a hidden field, which each every radio button and checkbox field on the form has to have if it is lookup-able.
This is such a common function that we have it as part of our boilerplate.js, which we include on all projects. So I wanted to submit it as a feature request. It would be great if the Lookup Rules section had logic like "Check <checkbox option 1> if <database value> equals X".