In the scene onboard the Enterprise ship, he is being interrogated and tries to fire a phaser, but it doesn't work. He tosses it at the FBI agent and runs off. Didn't he just leave future technology in the hands of the government?
shareMost likely. If it doesn't work, th er y may just pack it up for evidence and forget about it.
shareLikeliest outcome is that the guy who caught it just threw it away and it got buried in a landfill, or it got put into an evidence box and was thrown away years later.
Because no case ever would have been filed or prosecuted, as there was no serious crime and the defendant disappeared from the hospital, and as far as anyone on the Good Ship Enterprise knew, Chekov was just some random nutball who wandered in off the street.