I almost got into a piece of that plastic bird netting that was draped over some of the plants. That would have been bad but not as nasty as barbed wire. I guess you really have to watch out for any obstacles in and on the ground because the higher tine speed can do some real damage before you can react and shut it down. It would be nice if the control was the type that you held down and would release when you let go. As it is, It locks on and no hands are required to keep the tines running, which isn't really safe. I'll have a look at the new versions and see what they use.
At one time there was a junk pile where my garden is, I have probably removed at least a wheelbarrow load of plastic, glass and metal from that area. The barbed wire was rusty and I didnt see it until it had wrapped itself around the tines and killed the motor. I had to drag the tiller out of the garden between the grass the wire and a very adult words I got it out. I would think after 4 years of tilling the same spot, I would have all the junk picked out, but every time I till I find more junk.
I was on another forum a years ago and read story about rear tine tillers.
A man was using a rear tine to till his garden, it was one of those with the levers you have to squeeze to keep it moving. He stepped into a gopher hole and his foot slipped up under the tiller tines and got wrapped around the tines. When he let go of the controls, he got hung up and the tiller kept going finally running into the fence. When the paramedics got there they removed the tine assembly with his foot still in it and him to the Hospital. The man was diabetic and the surgeon had to remove the man's foot at the knee.
So be very careful when tilling.