I decided to give this a go with editing the widget and found it really wasn't too bad to do it. You'll still have to own the cloned version of the widget, but the original will still upgrade for you to merge with after an upgrade. Here's how you can accomplish this...
1) Create a new field True/False field on the 'sc_cat_item_guide_items' table (this is the table in the Order Guide rule base related list). Make sure to name the field 'Toggle off default' and then you can re-label however you want. We just want the field name to match what I've got in the script below. You can then check this field if you'd like the toggle to be off for a particular rule base option by default.
2) Clone the 'SC Order Guide' widget and modify the 'Server Script' portion of the widget to include the following code immediately after the 'item.included = true;' line.
// Query for the order guide rule base for this item to determine if it should be on or off by default
var ogr = new GlideRecord('sc_cat_item_guide_items');
ogr.addQuery('guide', $sp.getParameter("sys_id"));
ogr.addQuery('item', item.sys_id);
ogr.query();
if (ogr.next()) {
if (ogr.u_toggle_off_default == true) {
item.included = false;
}
}
3) Replace the 'SC Order Guide' widget with your new widget on the 'Order Guide' page
