I am only posting now because mdd brought me into this= as I have not posted for a while. Incidentally, I posted a response to mammele and leyzwer a long time ago but it was not posted so I cannot be bothered to write it again.
However, I fully concur with oomis that the parameters of “tsenyis” are fairly confusing but the rabbonim of this generation have decided to go “lechumro”. So be it- but ,as oomis writes, there are many.many grey areas!