I can't remember reading anything about the mob, without the book mentioning how Luciano set up massiera in the restaurant, while he went to the mens room.

why that story has been so accepted I don't know, but, it has been acknowledged as fact. ive probably read it in a dozen books,
now, after reading all these posts, with research being done.

I don't think that was what went down, the way I see it Luciano most likely wasn't there, no doubt he had a hand in setting masseria up. but, he may have conspired with maranzano himself.