Hi, you gibe the following recommendation:
We recommend that you use the same passphrase for your root password as you use for your LUKS encryption (unless you share your laptop with other trusted people who should be able to unlock the drives, but shouldn't be able to become root).
This might be misleading. As LUKS is able to store 8 different passwords for the same volume, you can share your laptop with 8 different people, each using his own, personal password to unlock the disk.