"It is experimental, but MAY be implemented in 2004."
HAS been implemented for 2004.
INDIANAPOLIS, IN (June 19, 2003) The National Federation of State High School Associations (NFHS) Softball Rules Committee adopted the designated player/FLEX rule at its annual meeting June 8-9 in Indianapolis, Indiana.
Go here -
http://www.nfhs.org/press/softball_rules_changes03.html
Not mandatory; optional for coaches; but is part of the high school rules next year.
WMB