How do small-time merchants detect fakes in China? Do they just not care and pass it on?
Small merchants are very cautious about money - they thoroughly check notes (even taxi drivers) so they are very unlikely to try and pass on fakes (it is a criminal offense to do so).
Is there some English resource you all recommend for figuring out which year had what kind of marks? I duckduck'd around, but it's mostly limited third-party sites... 
I live in China so you can see videos in many banks here on how to detect fakes (something to entertain you while you are waiting for your number to be called up when waiting) - am not sure what most westerners use but I would guess translated versions of such videos must exist.
BTW - I've only ever been passed two fake notes (both 50 RMB) in 7 years of living here (so it isn't quite as common as you might think).
