Yeah, I've looked into that a little and it appears that there hasn't been any reported bricking yet. And people seem to be using R4 cards as regularly as on a DS, so it just looks to be some good scaremongering on Nintendo's part.
Apparently some old R4 cards will work on the 3DS and some won't, I imagine it's only for DS games though and you'd have to get a specific 3DS R4 for 3DS games.
I haven't checked these £50 3DS' out yet anyway as the guy fell asleep, he lives next door and you can see him through his front window sprawled out on the couch

My Mum saw the black one he took into her work earlier and after a bit of investigating it turns out that it's the limited edition Zelda design one. Black, with gold design on it. I've never played Zelda in my life, but for £50 it's gonna be hard to pass it up.. so I reckon if I do get this 3DS I may have to invest in a Zelda game or two, too.