In #3320, @mirjak suggested that a different algorithm might be better to recommend enabling ECN and only disabling it if a failure is detected.

That algorithm adopts the same posture as the draft: that ECN is optional and that endpoints are permitted to be cautious in enabling it. If we want to adopt the view that ECN works and endpoints are required to use it unless it breaks, that's a bigger change.

I open this issue, while being aware that this is re-opening something we discussed and agreed previously, without there being new information to present. Chairs, if you do think we should discuss this, it's a design issue.