From the people who brought you:

"Ouch! His oversized ring pinched me. Well, I'm sure it's an accident, no need to worry he's collecting blood for a ritual spell against me"

"Hmm, sticky hands. Surely, he's just nervous meeting such an important person, not swiping my fingerprints."

"Is that a nicotine patch on his hand? Wow, I sure feel sleepy..."

"His hands are dry. I sure hope it's not because of the RFID dust we use to track anyone who touches our priceless artifacts."

and lastly,
"Was that a needle pinprick from his cyberhand? I have HOW long to live unless I do exactly what he says now?"

comes yet ANOTHER reason to never, EVER shake anyone's hand:

"Was that a slight tingle? Like when my skinlink is transferring? Well, nothing to worry about, I'll just e-mail my corp's top-secret plans anyway."

Yes, that's right, skinlink might be mostly safe during combat situations, but it is vulnerable to social engineering. Picture the following scenario: Your face is socializing and living it up at the target's party. The hacker is surfing dwarf por... er, whatever it is hackers do when you aren't looking, passing the time in the van outside. A signal comes in over the coms, the hacker goes to full VR. The face shake's the targets hand. It's a good, firm handshake. A bit of eye contact and some distracting banter. The shake lasts for a combat round, maybe two. That gives your decker a good three to six rounds to hack in and turn his agent loose, using the face's skinlink equipped com as an access point. A submersed technomancer might have four to eight rounds to turn loose a sprite, plenty of time to get past the firewall a comlink is capable of supporting. A few seconds more, and the face is back to enjoying martinis, and the hacker is back to wondering how those dwarven women keep their beards so trim. A few hours after that, and the paydata arrives by mail, courtesy of your agent or sprite.

Need more time? Plant a skinlinked RFID on him.

Heck, I'm tempted to give my technomancer a gun loaded with RFID darts just for skinlink hacking in a combat situation. It's not garunteed, but even if it forces your opponent to choose between spending his round picking darts out of his skin, abandoning his coms and gear, or letting you hack his smartlink, it's a win.

That is such an incredibly good idea. I /love/ the idea of hacking sometimes requiring that social element. The time factor makes it doubly exciting. Nice

All the more reason to adopt the Japanese (among others') custom of bowing instead of shaking hands when greeting someone.

Or its time to start wearing gloves.

why did you stop? leaving fingerprints around is a bad ting

Or don't leave all that info on your comlink when at a party? Some social engineering aspects also go into data security.

Also, it sounds like a great adventure area for the DM to set up and have the players do.

But for the PC's the DM can always screw you no matter what you do. So you might as well not worry about every little thing.

I wanna know why you think you can hack a skinlink just because you planted an RFID on someone.

EDIT: Hmm, I think I see. It's not so much an RFID as a gateway to his skinlink. Very Evil. My interpretation of the skinlink system is basically that anything you would normally wear with wireless ability also has a skinlink system built in. Because of this, I assume RFID tags fall outside of that usage, and don't normally have the ability to be skinlinked. On top of that, I don't think an RFID would be able to serve as a gateway. Not that you idea doesn't work, just that it doesn't use RFIDs. Of course, this interpretation is outside the scope of the SR4 rulebook, so how it actually works is up to the GM.

A RFID with Skinlink mod would serve as an gateway.

Time to restrict our skinlinked PANs to known MAC addresses then? No dodgy new subscribers for us

use a security or stealth tag, they have a system (read signal) of 3 so you could keep a respectable distance.