since some are concerned with the extended arm portion of this incident, i'll throw my 2 cents in here...
i have been training in brazillian jiu jitsu for a while now and i'll tell you what - my FAVORITE thing to see from an opponent is an outstretched arm. if you give it to me, im going to take it.
for those who would like a nice alternative, here's some advice: create what we in the self defense realm call 'a fence.' it's a non-threatening gesture that allows you to control where an opponent/attacker/aggressor will be in relation to your body, as well as providing a solid stance to strike from if necessary. in the case of those carrying concealed, it provides enough distance and leverage with only the weak hand to allow a single handed draw if needed.
this is a great guy, Ari Bolden - he run's a forum and youtube channel called 'Submissions 101' and offers some fantastic advice on several topics. here's the video pertaining to the fence, i think he explains it perfectly...
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the idea is that if you dont have to draw and fire... dont, right? it's supposed to be the last resort and in a case like the one the OP related... it would not have been justified - IMHO.