It was primarily an NHRA "Problem" perpetuated by one team using it (the Dodge Boys, leading to 2 additional teams to do it or attempt to), many had an idea it was being done, but no clear proof. NHRA were like common prostitutes, in receiving sponsorship money, BIG $$$$$ from the first teams primary sponsor. The money for NHRA was just too good to do something about the problem, and risk the loss of the BIG $$$$$. Then the explosion exposed the problem for all to clearly see, NHRA had to do something then, which was the rule book was finally corrected, and the problem went away. Most likely the BIG $$$$$ for NHRA went away also, I'm not sure.
NHRA regularly screwed their sponsors for years, especially during the 80's, ALL about receiving $$$$$, and screwed many of the racers when they could get away with it.
The Harley-Davidson sponsorship of Vance & Hines and the check to NHRA in 2009 or 2010 comes to mind here. Something in the area of $850,000.00 to NHRA. Then the rulebook change to allow V&H to have the sole use of their own engine, and no one else, their own bodywork, no need to be tech'ed, nor did V&H have to show the engine to anyone else.
$850,000.00 gets you some nice rules,..... not fair,..... just real nice, don't you think?
Around here, the NHRA was known as "Road Whores",.....such a fitting title.....