David's blog

I found this tip on lonely planet's website, a travel guide provider:

Guidebooks Confiscated
Travellers entering China by road or rail across the southeastern border, particularly the Vietnamese frontier, report that Lonely Planet China guidebooks have been confiscated by border officials. This is due to sensitivity regarding maps of China that do not include Taiwan. Travellers should consider putting a cover on the book to make it less recognisable and just to be safe, copy down any crucial details you might need while in the country.

http://www.lonelyplanet.com/worldguide/destinations/asia/china
The mainland people sure are sensitive towards Taiwan issues, but the tips shown above are really amusing.