1.  Does the factory staff/management take home the leftover food if there is any after a restaurant meal?  If you have traveled to China on business then you most likely have had a nice meal with a factory owner or other staff.  Those that take home the leftovers get big kudos in my book.  This is a behavior which represents frugality and good sense over losing face.
2.  How do the factory workers’ bathrooms look?  China factory floor bathrooms are notorious (as are other country’s).  Is there a decent effort by management to keep them sanitary and minimize the stink?  This represents placing value on hygiene which will most likely translate into production practices.
3.  How easy is it to get to a desired person by phone when you call the factory?  For any size business, being able to connect with the right person, quickly by phone, represents good organization and management.  Test this by calling the factory reception.
4.  At meetings and meals do more junior staff speak up and seem knowledgeable?  Promising young talent at the factory is a sign of a healthy working environment.  So is management that respects junior staff and encourages them to be heard.
5.  How do you feel when you walk in the factory?  When you visit the factory, how do you feel in that first 5 minutes when you arrive?  Do you feel comfortable and like you’re working with people you can trust?  There’s no substitute for gut feeling.
If you are feeling uneasy about something be honest and speak up.  Communication is the key to quality.