Installing things into run-parts or .d directories.
What if a package is installed, and puts a script in a run-parts
directory or into a .d directory, but isn't configured due to a
missing dependancy? The newbie "sysadmin" doesn't know to look for
it, and leaves it there, then gets email from cron. Per sends off a
tech support question.
This could be prevented by having a place (/etc/cron.scripts, or
/etc/cron.d/crontabs) to install things to, then require that the
postinst create a symlink during configuration.