Their perceptions of time sharpen considerably when it's time to end class, though, or knock off work. If the working day is 9 to 5, 9 is very nebulous, but 5, boy... focus starts sharpening at 4:30pm.
I worked with one of these cultural pioneers in a restaurant years ago who would always show up an hour late when DST ended, and then would manage to do the same thing when DST began, instead of being an hour early, of course.
As an hourly employee, the genius still lost an hour of pay both ways, but considered himself smart enough to not have to actually work that hour twice a year.