BPMN2 — Method of specifying a default SequenceFlow is awkward

I have looked at a few sample BPMN2.0 xml instances, such as those in the draft spec, those in the book 'BPMN Method and Style', and others found on the web.

In all cases, SequenceFlow elements are shown with a sourceRef and a targetRef, but no id. This seems reasonable.

However, I have now discovered that, to specify a 'default' SequenceFlow for an Inclusive or Exclusive Gateway, you must populate the 'default' attribute of the Gateway with a reference to the SequenceFlow. As I understand it, this reference must refer to the id of the SequenceFlow.

This seems unnecessarily complicated. To me, the obvious way of specifying a default SequenceFlow is to have a boolean attribute on the SequenceFlow itself, defaulting to false.

If there is a good reason to specify it as a reference on the Gateway, I would have thought it would be good practice to always assign an id to a SequenceFlow. Otherwise, to make one of them a default, you have to, first, assign an id to it, and then use the id as a reference on the Gateway. This seems awkward.

The current solution might be confusing if someone was building a BPMN model directly with XML, but we don't expect that to happen much.
The current definition is simpler for tools to implement default Sequence Flow and the end user should not be impacted.
By putting the default attribute in the activity and gateway, we ensure in a simple way that there is only one default sequence flow. If the attribute should be part of the
sequence flow elements, tools would need to validate that only one of the outgoing sequence flows have the attribute set to true.
Disposition: Closed, No Change