Even if it was possible to allow crack clients (possible, but it will f**k things up if people steal names), Argonath RPG does not support piracy and any talk about it. And I certainly see no point as to crack such an lovely game as minecraft. (Yes I have cracked it and then bought it. Buy it if you can because IT is worth it. Awesome awesome awesome.
And that is the point why cracked clients should be allowed to enter too:Some just can't buy it and not because they are too lazy,but because they CAN'T
Seriously,if i could,i would've bought it already :/
As for the name stealing,just use the whitelist system and IP check-track-whatever,it normally shows IP in the console,so not much of a problem