Though I have no idea regarding the RF tx concerns, I can speak a little about the privacy implications. first a little reading, Here is a link to the NIST-IR 7628, which describes guidelines for smartgrid security. Volume 2 focuses on privacy impact. http://www.egov.vic.gov.au/focus-on-countries/north-and-south-america-and-the-caribbean/united-states/trends-and-issues-united-states/information-and-communications-technology-united-states/cyber-security-united-states/nistir-7628-guidelines-for-smart-grid-cyber-security.html
it is already possible with analog meters to identify devices inside a home, simply by sampling the signal at the meter at an interval of less than 2 minutes. the faster the sample the more accurate. by comparing the signals to a database of common electrical devices researchers were able to profile device usage as early as 1992. obviously, up till now, most utilities coudn't afford the staff to sample most lines at that interval however.
The smart grid exacerbates this privacy issue, because it allows and in fact requires high speed sampling to accommodate Time-Of-Use billing, and because the meters can send usage information to the utility head end effortlessly with no additional cost.
the real issue with privacy however will not come for a few years: smart appliances. Several EDUs are already selling internet service through their smart meters, but there is effectively no option to firewall this connection as it travels over the power lines and any interference would be felony meter tampering.
So, imagine 5 years from now, you are buying a new TV. you don;t care about internet connectivity, but the device comes with it embedded, and there are very few options in the TVs menus for configuring it. It uses powerline networking, so in order to just turn it on, you have already connected it to the Internet. At this point, you basically have to trust your TV manufacturer to not report to advertisers what you watch, including stuff like pr0n. with SMART devices you have to trust the manufacture implicitly..
Another big focus for the smartgrid is Electric Vehicles. The plan at present is to have the car identify itself to the power network, along with its owners billing info, so that wherever you plug in to get a recharge, it appears on your monthly bill. this can easily be used to track you over long periods of time.
SG meter data can also be used to uncover hidden sources of power generation within your property, so if you hide your usage to maintain your privacy, that will likely be accessible to any adversarial party that requests it.
So, a well monitored smart meter can be used to tell your schedule, the size of your family, when you are home, when you are away, your approximate worth, enumerate your devices, log how/when/where (in your house) you use them, track your internet usage, how far you travel each day (and possibly where you went), the day of the week you go to the grocery, and what ever any device you plug in decides to send to third parties, all with no indication that anything is happening.