"I've seen clerks try to insert slips 5 or 6 times and then watch another clerk clear the machine and the tickets are printed the first time."
If the problem is that the right button needed to be pushed it doesn't matter who inserts the slip. OTOH, when the clerk does the same thing each time the slip is inserted, either the button(s) they're pushing only works the last time, or there is some other transient problem with the machine.
"if the machine is ready to accept a pick-3 bet because the clerk didn't press 'start over' and tries to run Mega Million play slips, it might not read them."
Since the machines aren't a new idea and the bugs have been worked out, wouldn't it make sense that the machines recognize the slips for different games? Assuming you've had to use new slips for game where the matrix changed it should be obvious that the machines won't accept a slip for the "right" game unless it's the current slip. Of corse if the designers can't make a machine that knows what the slip is for, why would you trust their software? Buggy software could cause problems just as easily as a physical problem in reflecting the laser. I'm certainly not saying that most errors are a machine problem, but I'd be extremely surprised if the machines don't cause some problems.
"I don't know why Mega Millions tickets can't be canceled"
Because there's no incentive to the lottery in cancelling tickets. Selling tickets that are mistakes is more profitable than not selling them.
"Different subject but what if somebody who lived in a state that doesn't allow anonymity, spit the jackpot with someone in another state that does. Would a court rule that state must prove there was an actual winner and must divulge the name because it is public record?"
What if the person who won the first MM jackpot after somebody from Ohio won about $270 million and remained anonymous sued to see if there really had been a winner in Ohio? A lot of people worry that lotteries might somehow manipulate the game to prevent winners or decide which numbers do win. Suppose the state simply claimed they had sold a winning ticket and that the winner chose to remain anonymous, and simply kept the prize for the state treasury? It really doesn't matter whether a prize is split among multiple winners or not. Either there is enough evidence of fraud to get a court order for the records or there isn't.
