Speaking for myself, and I suspect many other Lexus owners, thank you so very much for this information. I was stuck in the Rita hurricane evac and could not determine alternate routes because of this limitation. Traffic was moving at a crawl and provided little opportunities to access the nav system to determine alternate routes. This info would have been so helpful for my wife to search routes while I dealt with traffic.
When I talked to Toyota about a fix for this problem, this solution was never mentioned and I was told that any modification to the navigation system would void my warranty. It is my opinion, they have made the tradeoff on litigation vs customer assistance and satisfaction.
Again thank you for this information