Urgent processing option

Hi,
I am currently in Australia for an exchange semester with a moroccan passport. I would like to submit my tourist visa application at the Chinese Visa Application Centre Services in Sydney 5 days before leaving to Shanghai and hence I chose the "Urgent" Processing option to get my visa in 24 hours. Do I need to justify with a valid reason why I asked for the "Urgent" processing option? Do they usually give a refusal for a tourist visa? If so, what is generally the main reason?

Thank you for your help.