Not sure if this is worth the calories burnt in brain effort, but the insults command appended to the Defaults line does not appear to be working, should I assume that its been left out of the frugal nature of microcore ?
#
# This file MUST be edited with the 'visudo' command as root.
#
# See the man page for details on how to write a sudoers file.
#
# Custom Defaults
Defaults timestamp_timeout=2
Defaults passwd_timeout=1, insults
# Host alias specification
# User alias specification
# Cmnd alias specification
# User privilege specification
root ALL=(ALL) ALL
tc ALL=(ALL) ALL