Astrid Silva remembers getting a new dress, her parents dressing her young brother in a suit and her father taking a rare day off from work to drive to an office where her father once again was tricked out of family savings for a green card.

The family could hardly afford the car trip and the day off work, but that was the day they thought their life would change. Instead, they were unknowingly sinking deeper into a fraud scheme of people they thought were legal immigration experts and who ultimately swindled Silva's father out of $11,000.

"We got to the entrance and there were a lot of other families with us. He thought this was the day he was going to get something," Silva said.

Silva introduced President Barack Obama in his Las Vegas speech the day after announcing plans to use his executive authority to shield millions from deportation and make other reforms that Congress failed to do. The president held her up as an example of the best of America and its immigrant roots.

But her family's immigration story also is an example of what may lie ahead for some of the millions of immigrants who may be eligible for Obama's immigration executive action. Like the Silvas, their eagerness and desperation make them prime targets for being fleeced at the least, and at the worst, ineligible for future immigration benefits.

Every time there is a rumor of immigration legislation or of a potential action, lawyers and others who assist immigrants start bracing for the cases of immigration shams, said Michelle Mendez, senior managing attorney for Catholic Charities Archdiocese of Washington.

Mendez said she is already hearing that the secretaries for a "notario" who was prosecuted and is serving a sentence are telling immigrants he'll be back to help them.

"We are concerned about the community being defrauded and I've had to salvage a lot of (immigration) cases after notario frauds," Mendez said. It's a heavy lift and not easy to untangle such cases, she said.

That's partly because the fraud falls within a patchwork of laws and regulations and because immigrants are usually reluctant to report fraud for fear of being deported.