The difference between AA/twa and this propsed DL/US deal is that DL is not in immediate danger of shutting down for lack of cash. If all of DL's employees were union, I could not imagine them waiving their seniority protections like the twaers did. However, if I was a DL non-union employee, I would be concerned due to the duty of fair representation that US's unions owe their memberships.
The twa F/As got stapled. About half the twa pilots were partially dovetailed while the other half was placed at the bottom of the list. twa mechanic/ramp went to binding arbitration where they retained full seniority at their bases at the expense of nAAtives.