CentOS, Ubuntu, Debian

I don't see any big danger in user thinking that server is installed – any attempt to run mysqld_safe will clear it out. There are other things that also depend on server being there – scripts/mysql_install_db, for one. While I can't right away think of a situation why they would be needed, I bet there are users that somehow rely on it, and will complain about breaking compatibility if we remove it. However, I don't have a particularly strong opinion on the subject, I'll keep it open for further decision.

On our side, having these files in client install directory screwed up our MySQL server detection script, which is part of our install script.
Please note that these file where not installed when building Oracle/MySQL client, that's why install scripts of our product where broken during MySQL->MariaDB migration. This could also happen to other users which migrate.

Furthermore if one build different version of MariaDB client and server, this could lead to inconsistency (i.e., depending on the way $PATH is set, use client mysqld_safe to launch mysqld whereas there are not compatible).

Regards,