Victor: finger and joint locks are fun for sure - a point is that the principles of joint locks themselves seem to vary little between Arts...it's the setting them up via entry strategies that appear to differ more than the 'techniques' themselves. JJ has their way, Chin-na has theirs, Aikido has their own, etc. The 'setting up' is what makes a system interesting moreso than the static techniques....and each Art can screw someone up given a antagonist pointing a finger at them.
Jim: 'offend' ? not even a little.
In person, if someone says a technique/principle/concept draws uniquely from Ryukyu fighting arts - I take it at face value, since the person presenting it can call what they are showing whatever they want. On a forum, reading it, if someone chooses to describe an armbar as 'an ancient armlock from Greco wrestling' instead of just calling it an armbar - it sortof gives the impression of a marketability spin using terms that can't be verified (even if it might likely happen to be accurate).
like you say, 'Ryukyuan Ti' cannot be verified, therefore of course it will look similar to principles found in other Arts...most likely since it is exacly those other Arts the person presenting it as an ancient system is drawing from.
Even if I could, I'm not trying to discourage drawing from other Arts, nor am I eluding to 'ineffectiveness' of any sort - even if I were qualified to judge (which I'm not). anyway...off-topic.
harlan:
http://www.kungfulibrary.com/shaolin-chin-na.htm