gpg(1) says that --quiet means "Try to be as quiet as possible", but:
0 dkg@alice:/tmp/cdtemp.rxik89$ export GNUPGHOME=$(pwd) 0 dkg@alice:/tmp/cdtemp.rxik89$ gpg --quiet --batch --pinentry-mode=loopback --passphrase '' --quick-gen-key 'test user <test@example.net>' 2>stderr 0 dkg@alice:/tmp/cdtemp.rxik89$ cat stderr gpg: key 3F59B7E221089762 marked as ultimately trusted 0 dkg@alice:/tmp/cdtemp.rxik89$
This causes problems for me with test suites that are designed to consider any warnings sent to stderr as a sign of a failure (e.g. autopkgtest).