Everyone else has talked about why you shouldn't do it and I recommend you take what they say seriously. However, that's how I learned to fight....
...It will teach you a way to fight if you last long enough to learn anything.
This brings up a good point. I would agree that it is possible to learn
some things about fighting, or effective self defense,
over time in these kinds of unorthodox training environments. I am sure that there are many who have been lucky enough to survive and become very skilled.
Of course, there is a tendency for this to be a "trial and error" type of learning environment which typically takes longer than if you learn from someone who already knows what they are doing. Also, the warnings from others come, not because you can not possibly benefit from backyard shenanigans, but because of the great risk to life and limb.
As I read the above post by MacIntosh, I agreed with the general point, and couldn't help but realize that many people do things this way. However, a thought came to my mind in which I compared this process to the discovery of flight. Although Orville and Wilbur Wright are noted as being the first to achieve sustained powered airplane flight at Kitty Hawk, North Carolina on December 17, 1903 (quick history lesson), you might say that they were not the first to fly, but the first to not crash and die while trying.
Many other inventors tried, unsuccessfully, for years to build and fly airplanes. Many of them died in their early test flights. What if the Wright brothers had died in accidents before 1903. Discovery of flight might have been delayed for an unknown period of time, and it would have been to someone else's credit. Perhaps one or more of the previous inventors might have been genius enough to have invented the first airplane
before the Wright brothers, but never got the chance because they died from an early mistake.
Yes, sometimes we take risks for the sake of progress, but it is wise to take calcualated risks with expert input and experience. By the 1900's, the Wright brothers were already very knowledgeable and successful inventors, and engineers. They ran many tests on more than 200 wing designs, and over 1000 glider flights. They were certainly not amateurs playing around in an open field, or someone's back yard. Perhaps those who died trying to do what the Wright brothers did were not so careful, and calculated in the risks they took!
Just something to think about.
CM D.J. Eisenhart