I was sitting in the third row, and knew it was coming, so I held up my money. Natalie (Gary Coleman) instantly came over and from the stage leaned over and I got to put the money in her hat. She gave me a huge smile and a big thumbs up, which was just awesome.

No one around me knew what the heck was going on.
If you have money and hold it up, the cast will do what they can to come to you. I think two of the cast members go out into the middle aisle of the orchestra, one or two cast members take care of the first few rows. And I know that the understudies take care of the mezz level - at least they did when Barrett was understudying John.
When I saw it nothing was taken from anyone, but if you have special things to give them during "The Money Song" they will take them, as long as they see it. Just hold it up high!
Hope this helps!
~Jessica
"If you start from a place of joy and charm, you can get away with a lot in the second act. It may be that that's my life. I'm not sure."
~Roger Bart