Originally Posted by
cxfan1960
I suggest you don't switch between different passports to avoid unnecessary hassle. That wasn't the intention for the secondary passport anyway.
HUH? USA authorizes second passports for its citizens who travel often to countries that require visas. The idea is that you travel on one passport while the other one is sitting at a consulate as part of a required visa application for future travel. If this applies to someone, it is the intention of the USA's willingness to issue a second passport.
Second passports where one is ordinary/personal and the other a diplomatic or official passport are a bit different. I suspect that someone should not enter China on a tourist visa with a diplomatic/official passport.