Relying on gpg exit code 0?

[Adam Funk]

Should I be confident about using gpg's return code 0 in a script (run 
automatically by at or cron) to make encrypted backups?  Example:

cd /backup/directory
tar cf user1.tar /home/user1
gpg -er 0x01234567 user1.tar && rm user1.tar

Thanks,
Adam