Your broker lends your share out. I borrow it. I sell it to Tom. I borrow the share from Tom's broker. Tom's broker and I both have no idea it's "the" "same

Your broker lends your share out. I borrow it. I sell it to Tom. I borrow the share from Tom's broker. Tom's broker and I both have no idea it's "the" "same" share I borrowed. Boom, 200% short interest on "that" share.