As Brian touches on, you cannot simply rely on ANY on-line attendance boundaries (not even the FUSD attendance map [ http://www.schoolworksgis.com/FremontUSD/schoollocator.html ] due to the fact the school district has the final authority to determine where a child will attend school.
The issue: Overloads!
You want to always confirm the attendance schools before you make an offer on a home due to overload transfers [call Pupil Services at (510) 659-2534].
Here's an example of recent Overload activity:
By the way, you can easily check attendance school for any address in Fremont, and many other Bay Area Cities, along with helpful stats (API trending, etc.) via http://www.SchoolAndHousing.com