Although, RHat is right that you can't just completely disable it due to update issues.
Not really. Security personnel, for instance, only enable wireless for updating when in secure facilities.
Ugh. That only applies for hacking the cyberware directly. You can still get into it through the PAN even if the implant's wireless functionality is turned off so long as there is a DNI, which is what the overwhelming majority of hackers will do anyways, because when you are faced with a choice of hacking a node that operates a single implant or a node that is like the master control for several implants, plus has all the target's personal info (SINs, bank accounts, paydata, etc.), and can be hacked from further than 3m away, which one do you think the hacker will target? Unless you are on COMPLETE radio silence (no tacnet, no comms, NOTHING) your ware can be hacked.
Although, RHat is right that you can't just completely disable it due to update issues. Tie it to PAN and be smart with defenses. If you are always the guy targeted by a Hacker either A) you need to tone down the I AM THE SAMMIE aspect of your character or B) the GM is screwing you.
If you have obvious ware, then you might as well beg hackers to target you in particular. Note the 'obvious' part. Natural looking cybereyes, hidden behind glasses/goggles? Doesn't count. Wired reflexes? No. Skillwires? No. Cybereyes that glow purple? Eh, sure. Obvious cyberlimbs with the bulk modification? You're damn skippy it does.
Of course, anyone who walks around with heavy weapons is another prime candidate for getting hacked, so if you have the Panther slung over one shoulder and a grenade launcher on the other, then don't be surprised if people start hacking you. Same goes for the people carrying a Barrett 121. Carry the overtly nasty with you, and people are going to target you first, same as the mage who has glowing mystical designs running over his lined coat.