In this specific case it may be that the court had defintie evidence to suggest the the Capt knew his crew mwmbers were drunk. At least I certainly hope so. Because otherwise its just crazy.
Bear in mind that not all airlines even have their crew staying in the same hotel, so how can you reasonably be expected to know what your crew are up to? You might be on a different trip schedule, even between Captain and F/O, and only meet one another 20 minutes before pushback, with the law enforecment officer just a few footsteps behind you. How are you supposed to know if the other person is over a limit that requires a machine to test a very small number?
I'm so knackered on the early checkins I'm stumbling around like a brain dmaged gerbil, and its got nothing to do with booze.
This is just one more example of the kind of thing I'm happy to be leaving behind in 2 months time.
CPB