You can issue Demerit Points to your children for a specified day by going into the Award Points page in your Adminstration area.  Here is a brief overview on how to do it:

1) Login with your Parent account and go the Administration area
2) Click the "Award Points" link on the left navigation
3) Choose the day you want to work with on the Calendar
4) Select the child account you want to work with
5) Click the (new) link in the Points From Parent area
6) The panel defaults to Award Points, but you can now click the Demerit Point link to   issue demerit points.

Demerit points will show up as sad blue faces for all design templates for now.  Our designer will create a custom demerit icon for each design template as time permits.