Like I said , you can make work against a 12 year old girl, but just because it is "not competition" doesn't mean you can make it work against anyone "on the street" who is halfway strong, partially in shape, or has a freshman level high school grappling background or 3 months of judo, sambo, or bjj.
And speaking of a little sambo, try that full nelson on someone with even a little bit of sambo and you'll get your knee broken.