Someone in the process of printing and distribution is in on the scam. They may not be able to prove who, but they can change procedures enough to prevent the same thing happening again.
I haven’t bought a scratch-off in a long time, but as I recall , back in the day, there was a “void if removed” sign on the ticket. If you removed it, it revealed the serial number of the ticket.
I assume that tickets sold at a particular store have somewhat sequential serial numbers.
That one game I linked to cited just over 10 million tickets in the game - I’d guess that’s 10,000 stores across the state each getting 1000 tickets? So if you had a losing ticket you could get the serial number - possibly know that the big winners would not be in that store’s sequence.