The graduates of a high school are bound to occupy superior positions in a society. Hence, they will be responsible for further development and prosperity and it's vitally important for them to take a brass of things, to learn to cater the man in the street. Community unpaid service- like charity work, teaching unprivileged children - could inspire them to find unexpected solution and remain conscious citizen.
First of all, in order to foster a competitive specialist a high school employs a wide range of teaching methods like seminars, conferences, lectures and many others. The mandatory community service could supply students with the reliable information how thing goes in realty. For example, it would be invaluable experience for future politician or economist to work for charity or teach children It will help them to perceive the urgency of people needs and it may point out a possible solution.
Secondly, a charity work allows graduates to remain human, to be modest and considerable citizen. The best example is the Royal Family. Their participation in the numerous charity events couldn't give absolutely plausible insight in normal people's life. Nevertheless it expresses their attitudes towards citizen and sometimes could spotlight their needs.
Nobody would argue against the fact that community unpaid service detracts valuable time from a high school's curriculum. It would be more practical to get some low qualified job but in your field. Therefore unpaid social service revive their patriotism, their responsibilities, moreover it it enrich them with new ideas and out-of-the-box solutions.