After my first rally this year, I posted about competitors NOT using their HANS/FHR properly - under Historics. But I think it applies to all motor sport, as we all have to start using them.
My message was to get someone else to check that your tethers are correctly secured, before you set off, especially when you are getting used to the fiddly clips.
See:
http://tentenths.com/forum/showthread.php?t=146452
John