It's an unfounded assumption, the reality is (and you can prove this with data) most people committing crimes today do it as an act of desperation. Professional criminals are definitely a real thing, but they'll exist with or without a basic income. However, if a basic income eliminates poverty, it may have a real impact on crime.
What about drunk/intoxicated driving? Ive seen a couple comments saying its ok if people smoke pot and play video games, but what about those who want to go out and drink? 33% of all traffic fatalities are alcohol related[1], and that adds up to be quite a few people. Ok, self driving cars will fix that eventually, but what about domestic abuse?