When things are easy by there very nature to acquire, why would people aggress to get them. The poor aggress to acquire what they need. In a voluntaryist system it is easier to acquire by ligitimate means that illigitimate, therefore by its very nature a voluntaryist system reduces act of aggression.
The wealthy aggress, because they can and its cheep. In both instances, the one concerning the poor and the instance concerning the wealthy, they both have shown do shoose to aggress due to its easier and less costly than do accomplish or acquire what they want ligitimately.
Most people don't want to steal, they do it because it is easier to go and steal from somebody else then to find a job and earn it. It takes very little time to steal, it takes quite a bit of time to find a job and work for it. In a voluntaryist system, there is an abundence and the potential for unlimited competition, therefore the price on items goes down. Thereby making the items more easy to afford, and easier to acquire than in the current system. The vast majority of those who steal will in a voluntaryist system work for the moeny instead of steal things. For the risk of getting caught would potentially be more costly in a voluntaryist system then in our current system. With drug not being illegal, the drug gangs would seece to exist, the price would plummet, and those who steal for drug money won't have to anymore.
Prostitutes would be legal, in a voluntaryist system. This would lower the price and risk of using one and therefore reduce the likely hood of rapes for sex. The rapes based on power, may still be around for awhile, but in a voluntaryist system, the woman wouldn't have to worry about going to jail if she harmed her attacker; like any potential victim does in our current system.
On to the wealthy. You and your friends seem to be affraid of the wealthy, in a voluntaryist system. The wealthy seek power and prestige; in a voluntaryist system they can earn it or go bankrupt trying to steal it. People think tha tthe wealthy will be highering mercenaries and then it is all over. There are two main parts to this: (1)the waelthy will still have to earn money. In our current system the vast majority of the wealthy individual's money is stored in paper assets, stock, bonds, etc. When the government goes away, those corporations which the wealthy have their wealth stored in won't beable to maintain their dominance in their markets because the government won't be ther to block new companies from joining. The wealthy will lose most of their paper assests value. (2)As companies are reconfiguring themselves in an environment without government protection, the private security professional, will quickly diminish. Most military and police join the private security because the salary is extrememly high -$100k plus for a new hire- as the other corporations start hemoraging money, they will not be so keen to be spending exhorbatent amounts of money on bodyguards and such unless they absolutley have to. Without the government to contract some of the war out to these security companies, and the corporations limiting how much they spend on this kind of stuff, the private security will diminish.
So with a severely hampered account, and possibly a company having to fight for every customer, and profession security on a decline; it becomes intirely impossible for someone to try and take over anything, but maybe a mini-mart. The costs of those kinds of excursions sky-rocket as the time increases. To try and lay seige against the market, the single individual or even a coalition of extremely wealthy individuals will work themselves bankrupt.
This is one of countless explantaitons of why utilizing aggression in a voluntaryist system will not work in the long run.