I doubt many explicitly pick their destination. But there's definitely a process of diffusion, where people are more likely to settle in jurisdictions amenable to their lifestyle and relocate when they're not. This is especially true for the largely transient community of petty criminals.

I can speak from personal experience here. Our local town had one of the toughest-on-vagrancy laws in the country. Then it go eviscerated in court, and the laws struck down. Without taking a position whether that was a good or bad thing, it's undeniable that the change was near instantaneous. Downtown became swarmed with aggressive panhandlers and park benches filled up with addicts on the nod.

It's not like the homeless in other cities were closely following the local court decisions, then strategically relocated. But by definition transient populations bounce around a lot. In previous times they might pass through before getting hassled, then thinking this place really harshes my mellow, then hightail it out of town. Now they show up, enjoy the good weather, panhandle off the tourists, don't get hassled by the cops, and what used to be a week-long residency turns into a year or two.

People do this all the time. People show up in San Francisco all the time with no money or belongings to their name.

It's very easy if you have incentive, or if you have nothing keeping where you are. Career criminals have every incentive in the world to move to a city where they'll be treated lightly, and often nothing holding them back.