So, for some reason I had unity-greeter-session-broadcast installed. This has a user session dbus rule:
start on dbus BUS=system SIGNAL=StartUrl INTERFACE=com.canonical.Unity.Greeter.Broadcast OBJPATH=/com/canonical/Unity/Greeter/Broadcast
which is the only dbus rule for my user session. When I removed unity-greeter-session-broadcast, I can no longer see all the dbus messages in upstart-monitor, and init --user doesn't seem to leak any memory.
So, for some reason I had unity-greeter- session- broadcast installed. This has a user session dbus rule:
start on dbus BUS=system SIGNAL=StartUrl INTERFACE= com.canonical. Unity.Greeter. Broadcast OBJPATH= /com/canonical/ Unity/Greeter/ Broadcast
which is the only dbus rule for my user session. When I removed unity-greeter- session- broadcast, I can no longer see all the dbus messages in upstart-monitor, and init --user doesn't seem to leak any memory.