As far as I can tell they are there to minimize movement and hold in the stuffing (cut up bike tube). I didn't even have anything there until a few days ago, just some electrical tape to prevent the FWD bracket from scraping the paint off the front fork. The natural tendency is for the FWD bracket to push on the fork at that point, not pull away. I suppose bumps could cause pull away transients. Anyway, the zip ties are so I wouldn't have to bother with the pipe clamps while I was still experimenting, I'll use the pipe clamps here and on the seat support later.
A ride report will be forthcoming, I did about 20 miles Sunday and had my first actual crash (fortunately at fairly slow speed)