Of course, if the folks who are smart enough to be scared of making mistakes won't write the software, that means it'll be written by folks who are too dumb to be scared or just plain apathetic...
The real trick comes not in preventing mistakes, but limiting the damage they can cause. I'd love everything I do to work perfectly the first time, but seeing that I'm human, that's just not going to happen. While I'm not in the medical industry, any mistake I make could easily cost thousands of dollars or more (I work on WePay's financial infrastructure) if I don't put appropriate fail safes in place.
