I thought for business travellers from certain countries, passengers can indeed enter Shanghai for no more than 24 or 48 hours without a visa. I recall a special visa desk at Pudong Airport for this where something is stamped in your passport upon arrival. The service is available only at Pudong and Honqiao. What you do during those 24/48 hours is up to you. You could quite easily get a 30-day L visa from the PSB office in Pudonog rather than go to Hong Kong, but you need to go down to the PSB in Pudong before your 48 hours are up. If I were you, I would head down there as soon as you land if it’s open. If you must go to HK instead then it is perfectly feasible to go to HK within 24 or 48 hours. There are loads of flights to HK every day. You could buy a ticket at the airline offices at Pudong Airport upon arrival, or if you are brave enough, find a local agent in town but that will take up your time somewhat but will be much cheaper.
It is correct that at your departure airport, check in will check your passport for a Chinese visa. But they don’t seem to bothered with this. In fact, the people there are unlikely to understand what a Chinese visa says unless the clerk is Chinese. Just tell them you’ll be going for just 24 hours on business.
