It isn't dangerous as long as you follow the safety protocol. This guy was very unlucky as he was wearing a weight training device made of metal, not just a watch or earring.
That's mostly true, but we're still finding new and interesting ways MRIs can kill people. E.g., non-magnetic metals are often safe, bit there was that guy who had his brain cooked as a spinal implant was the wrong length and focused the RF energy into his head. The additional protocol we developed is that objects can be certified safe for specific MRIs but not for all of them (and that being certified safe for a bigger machine doesn't say anything about safety in the presence of smaller machines).
Yes, they're pretty safe nowadays, but there's a lot of energy that gets dumped into a human body during an MRI, and I'd bet my last nickel that we haven't found every way that can cause problems.
