those geniuses broadcast computer programs via airwaves during a radio show. listeners would record it on cassette and play the program on computer. anybody else did that ?
First they would speak about the software (usually a game or utility tools), then they would emit the code.
There was no copyright till 1992 (and in practice till late 00s), so people just recorded that, copied, and then sold or exchanged on open-air markets.
BTW that's how CD Projekt (creators of Witcher and Cyberpunk games) started - 2 school friends selling pirated games - but they were a little older so they got their games by paper-mailing people in the west and not from radio :)
I remember in early 90s exchanging cassettes by mail was the way to go for C64 hobbyst in Poland. People advertised on teletext or in computer press and then sent each other several cassettes with software and empty cassettes to be returned with new stuff. Often they added their small demo program with personal stuff at the beginning of the cassette - it was some random sid music, bouncing balls and scrolling text with greetings and sometimes insults towards Atari hobbysts :)
Piracy was the rule for at least the next decade despite the law change. Nobody I knew at school had original software till 00s.