Haha, that's their 'Chinese' way of showing face and keeping control.
In the more advanced western world, we discovered the advantages of being well organized and communicating effectively with all layers of the workforce, before half of those middle aged Baijiu soaked baboons at SOEs were even born.
In China, managers/coordinators are often kept in dark till the last minute too. If they have a clue, they still may not know well enough what/how to pass on the info for the arrangements may be unclear too. The "communication" leads all the way up the food chain where they know and/or care little. Leaders/bosses in this country take ownership of people they lead/pay, so if someone isn't loyal s/he must be replaced.
In China, why do managers and coordinators always wait the very last minute to communicate with their subordinates? Sometimes they don't even bother but never admit their fault.