mysqladmin ping -u root -pmypassword returns successfully, even if the login fails

I wanted to use mysqladmin ping to perform a livenesscheck. I'm using the root user with an assigned password, thus the command:

mysqladmin -r root -pmypassword ping
echo $?

If login fails, the command writes an error message to the error stream - but the return value of the failed function is "0" although it should be "1" ($? retrieves the return value of the last executed command).
If you do this check with status instead of ping, the return value is "1", if login fails.