I agree proper use of any restraint is invaluable and saves futher injury and in some cases lives. However I personally think it has a very limited place in the world of door supervision, not least because there is not a independant body with enough experience to oversee the introduction. Also a point I would like to bring up is training and judgment Police officers go through constant courses and an intensive tutoring period where as the sia award does not, this could lead to many poor or wrong judgement calls leading to "Unlawful arrests" Citizensd arrest has a limited meaning and even if people think they are doing the right thing sometimes there judgment is not upto scratch. I personally would take great offence at being cuffed outside a bar.
With reguards to "quick cuffs" Yes they sometimes do cause injuries anything from scratches to broken wrists but they are a massive tool in the Policemans armoury, they are superb for controling a subject with the amount of pressure you can exert, one thing to bear in mind is we dont cuff nice people now do we its normaly drunken fools.
Platicuffs have there place to but I personally find these awkward when the subject is fighting and im on my own, good use as backup tho or for mass arrests.
I would be interested in taking a look at your course tho out of interest.