Yeah, good point itsme..
the old boards I am currently using are filled with nails, but i do spend quite a bit of time removing them.. OLD boards are ACTUALLY 1 inch wide, so i have to plane them... in order to preserve the blades in my planer I make sure theres no metal left.. A stud finder works pretty good for that, but missing one is always possible.
The boards I was using were straight from the mill. No matter what lumber you're using there is always a chance that there will be some metal in it from old forgotten fencing that the tree grew around so now the metal is actually inside the wood, not visible from the surface.
As to why I take risks... Life seems to have some of those. I have been around construction for a long time and find that most of the time if I pay attention to everything, I'll be fine. There are freak accidents though, so no guarantees. A guy has to make his own choices about these things. I'll continue using my saws.
Speaking of saw safety, have you all seen the "Saw Stop"? It's actually been out for quite a few years now and I've still never seen one in person. If you're interested, a quick search will take you to a video that's pretty interesting.