I have not been able to reproduce the HSM violations. I rebooted 20 times, cold booted, booted with battery, replaced battery and booted, tried 2.6.32-19 and 2.6.32-20, all of these seem to work without problem.
Previously (after the fix went in) I sometimes got the HSM violation, but only on boot, I was not able to trigger it by manually running udisks-probe-ata-smart.
I have replaced /lib/udev/udisks-probe-ata-smart with a script that generates a trace, so if it should cause an HSM violation again, it should generate a trace output.
My understanding of this bug is that it is only related to running of udisks-probe-ata-smart, which should only run at boot (unless repartitioning the drive). But some reports seem to indicate failures after boot (e.g. #234).
The workaround did seem to work for me.