I see my main point (or question) has been missed.

Some here are arguing that you don't need any sort of advanced
underlayment under the shingles - even over the eaves where flowing
water can freeze and/or back up and get under the shingles on
low-slope roofs. If you feel that ice/water membranes are a gimic or
aren't needed, fine. You don't have to follow this thread.

For those (like me) that think an ice/water membrane (as opposed to
tar paper) is the smart thing to put over the eaves, all I'm wondering
is why the membrane has to be peel-and-stick instead of just being
nailed down. It is the FUTURE situation of dealing with the membrane
being stuck to the deck that I'm wonding about (and apparently IS
causing problems in re-roofing situations).

Look. They used to "glue" 2 sheets of 15-lb felt tar paper together
and use that over the eaves. But even in that case the resulting
sheet was never "glued" to the wood deck - it was nailed.

Again, it's NOT the membrane (water-impervious-ness) that I'm
questioning. I just don't see why it has to have an adhesive surface
and become essentially glued to the plywood deck. If it was just
nailed down, with the shingles put on top, then I don't see how water
would EVER get under the membrane and contact the wood.