There are many colleges in Philadelphia. A popular activity of many college students is drinking alcohol. This is true for both the students who are at least 21 years old and those who are under 21. As it is illegal for people under 21 years old to buy alcohol, in order to drink it someone needs to provide it to them. This can be someone selling it to them or bringing it to a party for underage people to drink.
The person who sells or provides the alcohol to a minor in order to facilitate underage drinking can get into as more or more trouble than the underage person who drinks it. In Pennsylvania it is a third degree misdemeanor to intentionally and knowingly sell or furnish alcohol to a person under 21. This includes purchasing alcohol with the intent of selling or providing it to a person under 21. The penalty can include a $1,000 fine for a first time offense and a $2,500 fine for every offense after that.
However, just being charged with this crime does not mean that the person will be convicted of the crime. Everyone is innocent until proven guilty. There may be defenses available depending on the facts of the situation. The person must knowingly and intentionally sell or provide the alcohol. So, if the person did not know that the individual to whom they were providing the alcohol was under 21 years of age, then they may not be convicted of a crime.
Many people under 21 years of age consume alcohol in Philadelphia. In order to drink this alcohol, they need to rely on others to get it for them or sell it to them, which is also illegal. People charged with this crime are not automatically guilty though. However, this is only general information and not legal advice. Experienced attorneys understand the potential defenses and may be able to protect one's rights.
Source: Pennsylvania General Assembly, "Title 18 §6310.1," accessed on January 19, 2015