The easiest answer to the question asked is that the preponderance of "Borneo beads" that actually were made at Venice, is much larger than most people suppose.

I would be more inclined to say "SOME are not Venetian." And this would include beads from India, Germany, and Czechoslovakia. and, of course, some ancient beads (mostly from the Islamic Period—but routinely believed to be "Roman," or "from the Queen of Sheba").

And this is a topic that can be discussed on a bead-by-bead basis. However, the topic is approached in my 2010 paper for the Borneo Bead Conference.

JDA.