Economic factors and crime
That there are relationships between economic conditions and crime are well-studied. Economic conditions are not the only cause of crime, and nor should economic conditions remove any personal responsibility for crime, but certainly knowledge of these relationships allows us to lower the likelihood of crime by changing the circumstances.
So what are some of these economic motivators for crime, and how would a giftmoot economy affect them? Some of the main motivators are financial distress (the motive for a crime), the possibility of selling stolen goods or otherwise obtaining exchange capacity (the means for a crime), or power inequalities (which provide a way to get away with a crime). A giftmoot economy reduces all three of these factors, and the happy result should be that a giftmoot economy would lead to less crime overall.
Financial motivations for crime
There are two main financial motivations for crime. The first is financial distress, such as poverty. If a person in an exchange economy cannot get enough to eat, to pay rent, or obtain medicine, there is an increased motivation for them to use illegal means to achieve this goal such as theft, breaking and entering, and violence. Studies show a link between the stressors of financial difficulties (as well as political exclusion) and behaviours such as substance abuse and addiction, which are also motivators for crime, as people seek to get enough money to pay for more.
The other main financial motivation for crime is to fund some sort of excess, such as "white collar crime" where employees embezzle funds to improve their quality of life even though it may not be one of financial distress.
In both cases, a giftmoot economy would provide different conditions. First, conditions of poverty should be reduced, because people don't needs jobs or savings or money in order to get essential resources for their lives. Rather than use violence towards someone, a person in financial distress would have greatly increased access to necessary resources, and this would be a far easier choice than violence or theft. Because there should be a quality of life increase and lower wealth inequality, a person should be less likely to want to commit crime to improve their own quality of life.
Financial means for crime
But perhaps more significantly, the means of crime would be drastically reduced in a giftmoot economy. Some of the major reasons for various types of crime are in order to gain financial advantage, which is something that requires exchanges and exchange-value. If a person steals a phone, it is not generally because they want the use of that phone for themselves, but because they can exchange the phone for money, and then use the money to satisfy their own needs. But in a giftmoot economy, there are no legal options for exchanging goods for money (and no money), which means there are two huge barriers to financial reward from crime: one, that there are far fewer people with whom to ultimately trade the good, and two, that they would need to get exactly what they need from the trade, because widespread use of money would not exist.
So nt only would people be less motivated to commit variuos crimes because less people would live lives of financial distress, but crimes such as theft would not be a useful means to achieve the goal of financial stability.
Non-financial motivations for crime
There are some non-financial motivations for crime that would also likely be reduced. For example, a giftmoot economy would likely include better mental health access, which could have a positive impact on the incidence of maladpative behaviours, including violent behaviours toward others. Changed economic conditions would also allow for greater independence and lower incidences of financial control, leading to less people being trapped and exploited in circumstances such as jobs, family homes or relationships.
Wealth inequality and crime
There is also another category of crime that should be significantly reduced, and these are crimes of dehumanisation and exploitation, many of which occur because of a gap between the perpetrator and the victim in terms of wealth or status. This occurs when one group of people see another group as undeserving, lesser, or deficient due to their lower status, and thus feel less inhibited in how they can treat these people.
A reduction in wealth inequality - and especially a fundamental change in wealth that would dissolve the billionaire and millionaire classes - would lead to less perceptions and occasions of dehumanisation.
In addition, the very wealthy often have the capacity to buy their way out of trouble, with the ability to hire excellent lawyers, tie up court cases in extended legal battles, outlast poorer victims in legal cases, pay fines and buy off witnesses. These factors, too, would be fundamentally reduced.