Originally Posted by SamuelS

If you use multi-city on delta.dumb, you can often book "nested" back to back tickets all in the same itinerary, and they price up all at the lowest fare bucket applicable.

If I can book it and ticket it on delta.dumb as one of the offered total itinerary options, I would not expect anyone at Delta to come after me. If their own website allows it, how am I, a humble layperson, expected to know that what delta.dumb is offering is not allowed per some archaic ticketing rules.