First, I always play my own numbers for all types of lottery. For a lotto game with a big jackpot, I would find out the numbers from a very reliable source which in most states would mean being able to view the drawing on TV (but not in DE, no more televised drawings of any type, so I go to a retailer and ask for a report ticket for the particular lotto game and check my tickets). I usually know pretty quick when I see the numbers for a jackpot game, if I have winners, as I wheel in small number systems and know the win guarantees. I never throw away any lottery tickets. I take them home and put them into a box until the end of the year. As others have posted, losers can be deducted from winners at the end of the year to offset taxes if one files by deductions. No good for a standard deduction filing which I normally do. But there could come a time during a year when that might change and having the tickets around could come in handy. I can always trash them when a new year begins. I would never trust a store clerk. They could come up with all type of scans. For example, suppose he had several losing tickets of various amounts laying by his machine and you weren't able to see them. When you give him a $5 dollar PB ticket, he picks up his loser, scans it, and you hear that it is not a winner. He hands you back his loser and you don't pay any attention, but toss it in the trash can. After you leave, he scans your ticket worth a $100 or $5,000....keeps it and keeps his mouth shut. Waits for a couple of months before claiming if it requires going to the state lottery office, and tells no one he won. That would work good in DE since big winners can remain anonymous. Most people that do not care enough to check their own tickets will not think anymore about it when told their ticket is a loser. If you did catch him because you knew your numbers, he could always lie and say he made a mistake, scan your ticket which more than likely is a loser anyway considering the odds of PB, and give it to you. And if it were a winner, probably only the PB of PB and 1 white ball. And to be a really smart clerk, he could tell by looking at the ticket whether it was a quick pick by machine or numbers the player picked and not mess with it. Here though, you would think a player using enough thought to pick their own numbers would also check their own tickets. Just some thoughts about the topic.