this is ridiculous. i know ill probably get yelled at for this, but if it were a stupid part time job (such as a restaurant) and this happened. eh w/e, as long as the jobs getting done and people are happy.
but these asshats are building motor fucking vehicles. things ppl trust to work properly when used properly. their lives depend on it. fire all and stop their pay immediately.
you can joke about how it explains the shitty quality, but its definitely true. that and general incompetence. these are just the people that were stupid enough to get caught. there are probably others.
oh, and there are plenty of ways around drug tests. im pretty sure some kind of notice is given (24-48 hours) and depending on the user, things can be done to pass a screening. even if there is no notice, drug tests cost money and time and are more often than not given only for pre-employment screening or if there have been problems on the job.
Life's hard. It's harder if you're stupid.