I don't think anybody identified the gap. To be clear, the gap stems from the legislation. The legislation gave the CTA the authority to make the air passenger protection regulations.
If you read the relevant section related to cancellations that are outside the control of airlines, it constrains our ability to make regulations to only requiring that airlines ensure that passengers can complete their itineraries.
Frankly, if the section had been more permissive, we might well have established a refund obligation as we did for cancellations within the control of airlines, but we were constrained by the language of the legislation. I don't think anybody at the time, not parliamentarians, nor consumer rights advocates, recognized that the gap in the legislation and regulations could be as significant as we now realize it is.