Why TIGER/Line can be a bad source of geolocations

I came up with this neat map in Google Earth, showing the difference between Google's coordinates for some addresses in Palo Alto, CA, and a line connecting those to the TIGER/Line-backed geocoder.us coordinate, colored blue-to-red based on how far off it is. The TIGER/Line data only has endpoints for a range of addresses, and the geocoder.us Perl module tries to do a linear interpolation to get addresses in the range. Obviously this doesn't work well for non-linear streets like this one...