Crime is essentially a form of parasitism that is only viable due to the proximity of hosts. A criminal can only profit if there are victims to profit from. The lack of mobility of housing stock today means that if hardworking people live in an area where burglers and robbers are present which break into their house and steal their car, since the cost of moving is prohibitively high they may choose to stay and tolerate it.
In the case of a modular seastead, if the seastead had a crime problem, hardworking people and businesses could detach found a new seastead on a new piece of water and establish an immigration system that didn’t allow anyone without a clean police record in. This would leave the old seastead full of robbers with no one to rob from!
I wonder if the existence of this option for floating infrastructure could dramatically reduce the prevalence of crime in watery environments?