Those are the passengers who are going to get on board at 9PM.
Those are the passengers going to get on board at 9PM.
I heard that it's wrong to remove "who are" from sentence 1, so sentence 2 is wrong, but I really don't understand why 2 is wrong. Can we think "who are" is implied between "the passengers" and "going"? Could you please explain why?
Is it because there is a difference in meaning between 1 and 2 if "who are" is omitted or because we don't know whether "who were" or "who are" is omitted in sentence 2?
Q1) Is this because sentence 2 can be read in two ways as below?
A. Those are the passengers (who are) going to get on board at 9PM
B. Those are the passengers (who were) going to get on board at 9PM
If my guess is correct, depending on situation, can 2 be correct as well if people are in a situation where sentence 2 is only read as A?
Q2) But why is it correct to omit "who are" from sentence 1 if other verbs such as moving or intending are used instead of "going"?