The City Council had the choice between adopting a resolution that would provide guidelines to help address public privacy concerns or actually passing an ordinance that would definitively protect privacy. The problem with a resolution is that it can be more easily discarded when situations arise that appear to be "an exception to the rule". Ultimately those exceptions become the watered down rule.
This was not an issue about not trusting the Menlo Police Department or diluting the law enforcement tools the Department has at its disposal. If those where the issues the City Council was focused on, the Department would not have been given the technology in the first place. To quote Mayor Mueller, this was the challenge of finding a careful "middle ground" that provides checks and balances to responsibly address privacy and abuse concerns.
Council can always let out the reins once a longer track record has established. In the meantime, safeguards that error on the side of privacy are appropriate.