This is out to all who have done this before, regardless when:
You have a free visa(no visa required if you're staying X number of days) entry but your stay is going to expire soon. and Perhaps you have decided cross the borders to obtain an extension from the date you leave mainland china.
Crossing borders at EITHER vietnam, taiwan, Hongkong, Macau (Though it taiwan, hk and macau is officially part of china)
Note: i did cross to macau from hongong and coming back again, in which i got an extension in hongkong from the day i left macau. but i'm not sure if it works from china-mainland to hongkong.
This is probably not visa run? because no visa is involved. But i'm not sure, so do correct me if you know
Thanks fellow backpackers/travellers!!!!
This thread has been moved to the Asia forum. Go to the new DISCUSSION: Crossing border+Visa:(visa run?) thread.