When running Compiz GIT, even with the Place plugin being properly loaded at startup, windows continue to ignore the status of the "workarounds" setting for the Place plugin unless the option has been un-ticked and re-ticked in the gconf-editor. For the rest of that Compiz session, workarounds work correctly.
Sorry about the phenomenal bug spam, guys. Adding xorg-team@ to the QA contact so bugs don't get lost in future.
Place is long gone now.