It works to repeatedly append to a file on one machine and `tail -f` it on another. Even an encrypted file. It just works.

As for collisions, a "conflict" is handled as you would expect on file syncing services, although all conflict resolution has to be done by the clients! (Even in the unencrypted public folders, the resolution of the conflict has to be signed. And in the encrypted case, obviously the server has no idea.) This is one of the many things that had made KBFS a large and interesting project.

If you really wanted to use KBFS as a transport layer, you could avoid the conflict entirely by each device claiming a file to write to, and each one in a folder can monitor the others' files.