Formatting issues with workflows can cause builds to not run

Feedback & Bug Reports
1

the following config file results in a build never being triggered:

workflows:
  version: 2
  build_and_test:
    jobs:
      - build
      - deploy_prod:
        requires:
          - build

if I just fix the indentation issue, builds get triggered.

2

Would this result in it simply not running? Or does the entire workflow fail and it says no workflows found?