Comment by Mtinie

It could be lethal if a guild member attempted to share secrets or sell methods to a competitive guild. An example:

"In 1754 the State Inquisitors of Venice learned that a worker at Daniele Miotti's factory had fled abroad with a copy of his master's books. Fearing that he would divulge secrets—especially in Bohemia, where there were important glass factories—they ordered his death."

Source: Zecchin, P., (2025) “Una condanna a morte di dubbia utilità: Sarebbe stato molto grave, per i vetrai muranesi, se il seicentesco ricettario Miotti fosse caduto nelle mani dei Boemi?”, Journal of Glass Studies 66: 7. doi: https://doi.org/10.3998/jgs.6939

Just how widespread it was for violent and lethal actions to be carried out in pursuit of maintaining guild secrecy, the evidence is murky.