I finally got around to checking my NFHS Basketball Handbook. I found these under Chronology Of Basketball Rules:
1965: Lack of action outlined in "Comments on the rules".
1982: Warning for lack of action reduced from ten to five seconds; Developed basic principles on lack of action in "Comments on the Rules".
I can't find when the lack of action rule was deleted. The oldest NFHS Rule Book that I have is from 1996-97, which does not contain a lack of action rule, so the lack of action rule was probably deleted sometime between 1982 and 1996-97. I'm sure that there are some veteran officials on the Forum who can look through their old Rule Books from 1982 through 1996-97 to find out when the lack of action rule was deleted.
