you really really can. Frankly, kids are brought up with certain beliefs, well brought up people that think theiving is wrong won't be pressured into becoming thieves simply by hanging out with bad people. I've met people and been friends with bad people, but if they choose to do something wrong I wouldn't join in because of who I am. Depending on what they were doing, if I found out they were involved in something really bad, I simply wouldn't be friends with them.
Sorry but, the parents are to blame for bringing up crappy kids. Generally people ignore the idea that people can be to blame for having bad kids because then if their kids do something bad they would be responsible, so claiming its not parents to blame gives themselves cover to some extent.
Now parents aren't actually responsible for the individual acts that other people commit, no one is responsible for other peoples acts(beyond kidnapping someones kid and saying go rob a bank or we'll kill them type situation). But they are responsible for bringing up kids capable of these kinds of things.
I'm not 100% sure, its never happened, but I'm physically capable of taking a life in self defence, or defending others, however I'm simply not capable of commiting a crime that hurts or endangers other people for a laugh, or for fun or personal gain. I simply couldn't bring myself to mug someone, or steal a car, I believe its basically completely wrong and would never do it. What people believe is what they are taught or learn to believe. Parents are very very responsible for that and if other people are teaching them bad things its their job to teach them the right thing to do. if you didn't, you failed.