I type these words with a (non-elective) series of metal prostheses implanted in my hand and wrist. Luckily, I don't set off metal detectors unless they're turned to extremely high sensitivities. But MRIs are out. I don't want to get into TMI detail, but let's just say that I have an ongoing medical condition that makes the inability to get MRIs a big setback.
Tread carefully with this stuff. Look before you leap.
You realize there are other large magnets in the world besides those for MRIs?
Demagnetizers... isn't the whole point to enclose the field? I'd also expect a warning sign or two, or for you to pay attention and know it's there. This is one of those "make your decision, and then live with it" things, and part of "living with it" is being aware of these things (and that acquaintances with more humour than sense might try to hand you magnets you can lift tables with).
Large electric motors... Dunno, have no experience of them yet.
Tangentially on the topic of MRI safety, there's a fascinating story of a police officer who got too close to an MRI. The magnet yanked the gun out of his hand and the gun went off despite the thumb safety being engaged. (Nobody was hurt and the MRI received only superficial damage.) Apparently the strong magnetic field pulled the firing pin block out of the way, allowing the gun to go off. Details: http://www.ajronline.org/content/178/5/1092.full
Besides, I've been exposed to serious magnets; the inverse cube law is my friend. Plus, even when I did come close to a strong magnet, all that happened was my implant flipped ends. In my finger, yes, but it wasn't painful (my implant is a cylinder, about as tall as it is wide; a disc magnet would have been much worse).
If by "unconscious" you mean asleep, not many.
If by "unconscious" you mean unaware, plenty. Try walking past these in a lab:
FYI: Neodymium magnet strength is of order 1T, same as MRI.
The implant is powerful for its size, but its size is _tiny_ (half a grain of rice is a good comparison). It's not going to be as strongly attracted as that.
I know that cochlear implants are very different from finger magnets (cochlear implants are attached to bone) but it does challenge some of my basic assumptions.
It should also be noted that it would take less than five minutes to remove the implant with a scalpel.
*I've had the pleasure of being MRI'd a few times in a 4 Tesla research MRI (normal MRI's operate around 1.5T) and occasionally I would get nerve stimulation due to eddy currents set up in tissue. An interesting feeling!
Would still be a headache though.