Given how intrusive they usually behave, I'd expect the average consumer printer to phone home, too. The solution in both cases is privacy laws.
I can put my home printer in a restricted vlan and block it from phoning back to HP. No laws needed (until the mfg tries to brick the device on loss of WAN access at least).
> until the mfg tries to brick the device on loss of WAN access at least
Didn't HP already do that with their Instant Ink program?
Or until the manufacturer includes a cheap GPRS module in the hardware.