Tuesday's immigration raid at Delta Downs--which resulted in the reported apprehension of 84 undocumented individuals--reminds industry stakeholders once again of a frustrating conundrum. On the one hand, they must navigate an environment of ramped-up immigration enforcement, and the potential that what happened at Delta Downs could happen at any other racetrack around the country. On the other, they face a long-broken system that makes sourcing legal immigrant workers a bureaucratic nightmare. "It's insanely difficult," said trainer Doug O'Neill, about a visa system that's necessary to properly staff the racetrack backstretch....