Well, yeah that's true, but, if there were 65 million people all using the sic Network, if half of one percent of those people were using the SIC at any one time, that would mean you'd have 325000 people talking at any time, all at once.
Which, would render the public SIC worthless, since, I seriously doubt anyone could pick out a single voice in amongst all that.
Let's have the moo generate 325000 random messages every few seconds and broadcast them on the public SIC! I bet that'd have a few more people ignoring it.
What I really mean is, what would always knowing if your SIC had signal really do for the game? Those moments you find yourself without SIC signals can make for interesting RP moments, often more interesting when you only discover you haven't got signal when you need one. Is it really that much of an effort to type 'who' every few minutes if you're using the SIC?
Personally, there are plenty of other areas of the game I'd rather see improved and developed than the ability to always know if your SIC has signal. I've said in the past, I'd like to see the SIC's communication functions removed all together. On the surface, it might seem like adding the feature you're asking for isn't a big ask, but, I suspect the code required would take up considerable time, that coders could be using to give us more cyberware, fun things to do, fixing bugs.
If you really need to arrange your moosex sessions, you can always use a cellphone, afterall.