To answer the OP’s question, there’s a story (real sorry dont remember this well) in the hakdamah to the sefer “kochvei ohr” where after he dies he comes to someone in a dream and tells him that for every person the ones who are the bais din (after 120) are the gedolim of his generation. Therefore, he warns, to be extra careful about the stuff the gedolim were very makpid on. I think in that generation the godol was R Yisrael Salanter who was always warning about gezel, so he was cautioning people not to steal.
For us thats internet.