More than likely it would become a back and forth thing since he could do the same.
Another answer:
The Time Machine will cease to exist, you would never heard about the time machine and never gone back in time. Simple as that.
Answer two: or maybe they thought it would be the best thing they ever heard.
They would be killed by other means
On the contrary, it would be much more reasonable assumption that no time machine is going to be invented.
They would be KILLED
you are going to be killed too...
Nothing would happen he can't die!
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you'd get arrested
Mankind would cease to be, then.
You would go to prison.
we would not get killed unless you recycle mebye
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