This is like judging a book by its cover ("… by staying in good company, you will become a good person and you will learn bad things in a bad company…"). I understand it is generally acceptable, but it is not true. It should be changed to stating having a strong mind or solid convictions about right/wrong things would enable a person to rise above the low-level characters of the company he keeps.
Leadership training can be found in such situations, where one refuses to go with the negative crowd and is able to influence them towards positive change. Instead of telling children to avoid bad company as such, and telling them to stay with good company, it produces 'followers' who generally will not do anything to start new things or take initiative, and most of the time wait for someone else to start whatever.
Children who developed positive character can be trusted to deal with the situations they face in their daily school or play areas. Having good communication channels with children helps very well to overcome wrong things and establish the right attitudes amongst the children's company. That's why there is usually school pupil leader selected as a role model to others in the whole school and especially amongst his peers.
Another scenario: in an car accident for example, most people will stand there shocked and doing nothing. When one person who recovers quickly takes the initiative to do something, then most people follow his instructions like "Call an ambulance", "pull the injured out before car explodes", etc.
Jesus had a lot of 'bad' company but he did well to change some into the opposite, and he himself didn't get corrupted by the bad company. Social workers who reach out to drug addicts or prisoners are not going there to join them in wrongdoing but to change them into positive, productive citizens. We can also do what we can do reverse the negative trend in the company we keep by being strong minded; impact and not be impacted and ignore the weak-minded society statements.