Voters in Minneapolis and Houston are among those leaving "I Voted" stickers at memorials for people killed by federal immigration agents.Why it matters: The tributes highlight how the Trump administration's unpopular immigration crackdown is motivating voters this election cycle.Zoom in: In Minneapolis, people are placing stickers on memorials for Alex Pretti, an ICU nurse, and Renee Good, a writer and mother, who were killed by federal agents in January.