How do I opt out of all face recognition? I have a right that my personal life not be exploited for advertising by a large company.
Most scanners to date have been moderately vulnerable to blocking devices. Say, a backscatter laser of some sort. And if personal identifiers are based on you carrying a broadcast device (e.g.: an info-leaking phone), one simple solution is ... don't do that.
I suspect that both the technology and its countermeasures will first be utilized by government (and corporate) "security forces".
Hrm ... related query: is it possible to build a simple device which would short out RFID scanners? If it becomes trivial enough to destroy the readers, then ubiquitous, obnoxious uses might at least become more expensive.
It's also got its abuses.
The tags are cheap. The scanners somewhat less so (especially when you add the labor cost of repair/replacement).
I'm not talking about killing in-store scanners and the like. However if I was aware of privacy-stealing roaming scanners in places they had no business to be in ... well. Raising the cost of data acquisition might be an entertaining hobby.
Here's hoping they thought of issues like: Guy wears his new "Google Goggles" to a racy late-night sales meeting, and Gmail serves how wife ads for divorce papers.
But really, the privacy implications are significant. I think Google knows this, and will take the necessary steps. At least, I sure hope so.