Possible Clues:

• Make love at sun-up? It's serious
• Student organisation after zero obligation
• Burden borne by university's old group of students
• Capulet opponent (R&J)
• Unpleasant necessity
• Burden a person usually conceals
• Responsibility concerning superpower
• When we pay for the drinks they are a burden!
• Old seamen take responsibility
• Upped paper round's load