I believe first of all, if someone developed a time machine the government would find out about it. They would confiscate the machine and erase you and your family from the face of the earth. The machine would be so regulated that no one would know about it. It is not like you would invent this machine and go time hopping on the weekends with your friends. That would not happen ever. To develop a working time machine would be the greatest invention ever. If you played your cards right, you could possibly survive and make billions off of the intellectual patent rights. But if you went through the US Patent office you would have gov't black helicopters hovering over your house in hours. I would film a successful time jump send it to the fed. gov't. I would then take a key part of the machine and hide it. I would then get the interrogation over with and inform them that the machine would not work without this part. You may be able to save your life and your families if you could play the game right.
But inventing this machine would be like playing with old, wet dynamite.