I suggest that the Smart Meter Opt-Out Workshop on Sept 14th in San Francisco at the pulibc CPUC auditorium (9:30 AM 4PM) be filled to overflowing with hundreds of demonstrators outside, if possible. This type of conduct should not be tolerated. Plse notify the CPUC Administrative Law Judge, Amy Yip-Kikugawa

John–
The only way is to make it physically impossible. If you happen to have a property secured by a gate and fence, lock the gate and make it as fortified as you can. However, they have been known to climb the fences anyway.

Below are some links to photos of the ways people have locked up their meters physically while still allowing the meters to be read.

https://stopsmartmeters.org/2011/03/01/defend-your-analog-meter/
http://www.bansmartmeters.com/blog/2011/03/hero-of-the-day-apartment-manager-blocks-smart-meters/
http://www.sfgate.com/cgi-bin/blogs/scavenger/detail?entry_id=59017

I know there are more. If readers of this blog can find more links and photos to locking up your meter, please post them.