I have fought this battle with DL on a number of occasions in the past. That is probably why DL is absolutely my LAST choice of partners. They not only sneak in my latent Skymiles # on connecting legs, they tell me they did not do it and there is no way to change it!
There's another thread going on DL UG's for NW elites. They sometimes offer to sell them at the gate. BUT, only if you agree to let them put your DL # in the record!
Great partner.........NOT.