Actually, it wasn't salary negotiation because it was pre-offer. It was during an interview, and the author lamented that "She didn’t get a call-back".

I agree that during salary negotiations it is less important to tiptoe around things. Perhaps it was a bit premature to have even inquired about the cap table in any way during an interview, unless the interviewer had just mentioned how many options would be offered to a selected candidate (which would be oddly specific, pre-offer).