This will never be possible because it is simply against privacy laws to gain information about someone else's system without their express permission.
not in the US. In the US, installing the software on your system grants it access to view any information that is contained on your system. The only privacy law that is in play there is it can't SEND the information out unless you give it permission. And, in any case, whether you registered mIRC or not isn't exactly private information. Private information includes things like address, name, credit card info, I doubt any judge would say mIRC registration status is protected information.
Think about it, if $isregistered is "private" couldn't $time be "private" as well? If someone knows what time my PC says they get a rough idea of where I live. Then of course mIRC sends my IP out to the server (of course it has to, but is there anything in the mIRC license that says I must agree to that?) So if you're going to tell me $isregistered violates privacy laws, then I guess mIRC as a whole would violate them.