What's "in time?"

Given the 40 minutes you quoted, I suspect she meant "before the plane departed," which is not "in time." Nor, necessarily, is "before the doors closed." She needed to be at the gate 30 minutes prior to departure for an international flight.

While it's correct that positive passenger-bag match does not apply when the separation isn't caused by the passenger, UA is still within their rights to mark her as a no-show if she wasn't there at T-30. (If there was an upgrade list, you can rest assured that #1 on the list was counting down the seconds to T-30, also).