Praise be to Allah.
This action is not correct. What they should do is to enter ihraam from the meeqaat. If they pass it without entering ihraam, then they have to go back to it and enter ihraam from there. If they do not do that and they enter ihraam from Jeddah, then they have to slaughter a sheep and distribute its meat to the poor in Makkah.
Shaykh Ibn Baaz was asked about this issue and he said:
They have to go back to their meeqaat if they were coming for Hajj or ‘Umrah. It is not permissible for them to pass the meeqaat without entering ihraam, because when the Prophet (peace and blessings of Allaah be upon him) defined the meeqaat for the people of Madeenah, Syria, Najd and Yemen, etc, he said: “These are for them [their people] and for anyone who is not of their people who come to them, wanting to do Hajj or ‘Umrah.”
So they have to enter ihraam at the meeqaat through which they pass, if they intend to do Hajj or ‘Umrah. If they pass the meeqaat then they have to go back to it. If they pass the meeqaat and do not go back, and enter ihraam after that, then they have to offer a sacrifice. Similarly if they are unable to go back, they should enter ihraam from the place they are in and they have to slaughter an animal that meets the conditions of sacrifice (udhiyah) and distribute its meat among the poor in Makkah.
Fataawa al-Shaykh Ibn Baaz, 17/36.