I would only go wireless if I had no other choice. Then I'd encrypt the living smeg out of it. The last thing I would need is my cyberware to be 'intercepted', ala GitS.
Yeah, the thing with GitS is not that it's unrealistic (to the contrary, they thought out the implications of their world really thoroughly), it's the power levels. It's not like everyone can hack everyone; there are a few wildly talented hackers, some of whom are in Section 9 and some of whom are guys like the Laughing Man, who can routinely do crazy shit. Most people have zero hacking skill, and not terribly high (legitimate) computer skills.
Which is really how it probably is in SR, too. Hacking 5 "only" costs 20 build points? Yeah, so what? Build points are for characters, not pedestrians. Oh, but someone can just spend several dozen thousand nuyen on an Agent and a bunch of hacking utilities and run scripts? Well sure, but those aren't exactly easy to get -- which really is a big deal for ordinary people. Shadowrunners have by default opportunities that ordinary people just don't have, or at least aren't aware of. The average person would no more consider learning l33t h4xing sk1llz building a hacker-in-a-box than they would buy a friggin White Knight LMG. They would also not be any more likely to improve their firewalls or install ice than the everyday luser of today. I mean hell, most people wouldn't even update their antivirus software if they didn't get prompted. Oh hey, I downloaded this thing to make my cursor turn into a smiley face or a dragon and now my computer is imperceptibly slower, that's weird, oh never mind.
It's like how people and especially institutions don't give two shits about protecting information. Identity theft and fraud and copying credit card numbers and all that stuff is so damn easy and bank tellers are not highly trained anti-forgery experts -- hell, they're not even full-time employees usually! You think some poor schmuck whose job qualifications consist of "I can count, don't have a criminal record, and own my own suit" and makes only slightly more than the kid at In-n-Out Burger can tell, or gives a damn, if that's a real check? Not likely.
And with technology advancing, all that shit gets easier and easier. Why? Convenience, carelessness, economics. People trust computers to do stuff that they don't understand. Individuals don't think they're going to be targeted because they don't really have that much to steal (ha). Unless it's a huge, rampant problem, almost nobody bothers with it. Banks -- BANKS -- don't safeguard against fraud until they have been defrauded and say "oh, how do we prevent losing more money in this exact way again?". And security takes time, so when your business depends on processing faster than someone else, you can't double- and triple-check every interaction.
More secure stuff is protected by better firewalls and better ice, and the fact that some of that ice can actually kill you is probably considered a deterrent, and that's probably correct too. But aside from that, meh. The kind of thing that's the target of a run, yeah, secure, high firewall, ice, a white-hat or two overwatching or on call, trace the connection and send some goons there -- or blow it up. Some guy's car, not so much.