I was thinking there's a slim chance, but a chance nonetheless, Apple will erect special boutique stores (or modify some of their most important stores) any time between now and launch day to offer demo sessions to the public. Letting people interact with products in store is an important part of Apple's retail experience so this has got to happen, right?
At the very least they will have to let people schedule a demo session at a store but will the demo take place at a random table in the middle of the store like when you schedule an iPhone setup? Where there's all sorts of noise and no place to comfortably sit? Meanwhile the built in spatial audio EarPods and relaxed interaction mechanism are some of the main selling points of the device which are not easy to appreciate in a busy Apple Store.
Come to think of it public demos will probably come *after* launch not before. Think back to the last time Apple introduced a brand new product that everyone wanted and was scheduled to release long after the announcement: Apple Watch. Apple didn't even stock devices in retail stores for a while after launch.