} > Protect users from being burnt by editing the crontabs directly: just
} > make /etc/fron/tabs non-user-searcheable...
} 
} This does not make the file un-editable.

I don't understand this.  If the user cannot search the directory in
which the only link to his file is kept, how can he edit it ?

# chown ronald /var/cron/tabs/ronald
# exit
% echo foo >> /var/cron/tabs/ronald
/var/cron/tabs/ronald: Permission denied.
% ls -ld /var/cron/tabs
drwx------  2 root  wheel  512 Apr  9 06:48 /var/cron/tabs
% 

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