How do you even rig the lottery? If the numbers are drawn the usual way (machine, spinning drum, balls) you'd have to use weighted balls, but of course the weights are checked before and after and the balls are in strict custody.

But in the US, where even the elections are computerized, anything is possible.

Rigging lottery is rare.

What is more common is to pay a winner more money for the ticket than the prize, to claim the prize for oneself, as a money laundering scheme. But this is not solved by removing anonymity, as it's hard to prove the scheme without the other person saying anything.

An probable example of this (in Spanish): http://www.levante-emv.com/comunitat-valenciana/2012/02/19/c...

See this investigative article from last week which lays out at least 8 or 10 people who figured out how to rig the lottery for certain types of games: http://highline.huffingtonpost.com/articles/en/lotto-winners...