Wired reports on a move by the Japanese government to ask websites to block users who "abuse" TOR.
I assume that TOR is being used as an example, and it would apply to any secure privacy tool.
The interesting question is whether this is simply a foot in the door on the way to banning anonymity, or at least making its use evidence of evil intent.
Currently, public privacy services make little effort to hide themselves. Traffic from them is easily detected as being from an anonymity system. If blocking becomes common, many systems may start implementing more effective stealth systems, which would make filtering anonymity for security reasons even harder.