Answering n to the confirmation prompt for submitting jobs via the manual launch script would launch the jobs anyway.
As Thomas pointed out, this is because Prompt.ask returns the response (in this case an "n"), which the if branch did not check properly.
Changed the check to use Confirm.ask instead, which returns a bool True/False based on the response.
Did not notice this during testing since the prompt had False as the default value, whenever I didn't want to submit the jobs I just pressed enter instead of writing in n.
While testing I also noticed that MyMdC has different behaviour for the xcal account and 'normal' accounts: xcal does not pass a scope through during auth, normal accounts require one. Added a simple check to only include the scope the account is not a dummy one (ending with @example.com).
Manually