Excuse me, if I miss something here, but aren't USB sticks practically used today the way that people tend to pull them off and forget that there was a process copying onto the device/file system or there was some indexer or hidden helper in background having operations on the file system. Not to mention people forget ejecting the device before physical disconnect. Today there exists all the more pluggable devices used as storage so ejecting becomes more and more unpractical all the time. So a process still writing onto an unpluged device should just be killed away automatically (the system administrator example is bad in this usage, I think) or die itself from eating resources like power and from complicating situations like suspending.
Secondly, can't a writing process conclude, there will no time in future to complete the request after a decent time has passed, when IO requests become time shared as was told on the Writeback section? I'm just an sysadmin, so I may get many many things wrong here.