One of the breakthroughs in stealth aircraft came from the book of a Soviet scientist ( https://en.wikipedia.org/wiki/Petr_Ufimtsev https://en.wikipedia.org/wik

One of the breakthroughs in stealth aircraft came from the book of a Soviet scientist ( https://en.wikipedia.org/wiki/Petr_Ufimtsev https://en.wikipedia.org/wiki/Petr_Ufimtsev ). So it's not surprising that free sharing of information can inadvertently helping rivals.