Ubuntu user not affected by sticky bit on Ubuntu 22.04

I experience a strange behaviour in stick bit on /tmp directory and flock command. Tried with two cases: Case 1: create file with Ubuntu user, root have no access to the created file. ubuntu@:~$ touch -a /tmp/ubuntu_user_created.lck ubuntu@:~$ flock -n /tmp/ubuntu_user_created.lck -c "echo 123" 123 ubuntu@:~$ sudo flock -n /tmp/ubuntu_user_created.lck -c "echo 123" flock: cannot open lock file /tmp/ubuntu_user_created.lck: Permission denied Case 2: create file with root user, root and Ubuntu user have access to the created file. ubuntu@:~$ sudo touch -a /tmp/root_user_created.lck ubuntu@:~$ flock -n /tmp/root_user_created.lck -c "echo 123" 123 ubuntu@:~$ sudo flock -n /tmp/root_user_created.lck -c "echo 123" 123 Permission in the two files: ls -la /tmp/ total 52 drwxrwxrwt 12 root root 4096 Oct 6 08:08 . drwxr-xr-x 19 root root 4096 Oct 6 03:42 .. -rw-r--r-- 1 root root 0 Oct 6 07:56 root_user_created.lck -rw-rw-r-- 1 ubuntu ubuntu 0 Oct 6 07:54 ubuntu_user_created.lck I don't understand why Ubuntu user can run the command flock -n /tmp/root_user_created.lck successfully, since the file root_user_created.lck is owned by root, does the flock command just want to open this file with read mode? If the flock command only need a read access, so why run the command flock -n /tmp/ubuntu_user_created.lck command with root privileges return permission denied?