Why did Friar Laurence agree to marry Romeo and Juliet in secret?

Remembering that their families - Motague and Capulet - were feuding, Friar Laurence agreed to marry the two teenagers in the hope that the families would make amends on the account that the youngest of their houses had seen past their differences. However, the Friar does not publicise the fact that the two are married, for fear of blame and contempt, and so the marriage is kept a secret until the two lovers die. Some argue that Romeo and Juliet would both have survived had Friar Laurence agreed to marry them, but not kept their marriage a secret.