MRIs can do scary things to metal
I've seen a video of someone attaching a scale to heavy duty web straps, wrapping up a chair in them, and measuring how much pull an MRI exerts. The thing registered over 2,800lbs before the straps broke (it REALLY wanted that chair). Throwing a stapler into an active one will turn each individual staple into an independent projectile capable of going through six inches of ballistic gelatin.
Even if the magnetic suction effect doesn't get you, non-ferrous metals will become antennas for the field. Just imagine magnetic induction sending lots and lots of electrical current through your sensitive piercings. Or worse, finding out the hard way that your gold earring is actually gold plated iron as it rips out of your ear at bullet-like velocities.