Re: final lock doesn't work
I sometimes like to study chin na or hapkido and I have noticed a willingness to accept the fact that locks are usually temporary in practitioners of those arts. Often they are combined with strikes and breaks of course (what Imaizumi Senei may point out as "old style"). If it hasn't been mentioned in a while, Tim Cartmell's work in that area is excellent...including his videos and two important manuals he translated from Chinese.
How long does one have to go before we can say that we've really got the hold? 10 sec? 15 min for the cops to show up? A good hold is great but I think that the ideal of the unescapable, never breakable pin is best studied as an ideal.