It's the subsidy, stupid.

San Francisco voters will go to the poll tomorrow to decide whether the City of SF should "encourage the development of a site in Hunters Point Shipyard for a new stadium."

Note that the text of this Proposition G says nothing about SF residents having to pay for any part of the stadium.

San Jose Mercury News columnist Ann Killion essentially called Prop G a lose-lose proposition for the 49ers:

If Proposition G wins, ... [it] could compromise the team's appeal to Santa Clara voters: Why should the small pool of Santa Clara voters pony up $160 million for a stadium when San Francisco voters have approved a measure that would cost [SF] virtually nothing?

If Proposition G loses, ... it ... would weaken the team's leverage with Santa Clara: removing their most viable alternative, while creating an anti-stadium climate.

This is why concerned residents of Santa Clara have been opposed to the deal all along: it's the subsidy. Thank you Ann!