Student rentals - request to move in a few days early

[Matt McCue]

Brand new to RE investing...I bought two 6 bedroom SF houses that were set up for student rental housing in June.  Tenants for this academic year move in Sept 1st.  A couple of students asked to move in a few days early.  We supply literally everything they would need to live (dinnerware, furniture, cable, internet and all utilities), except a bed.  Is it reasonable to charge them a prorated portion of a month's rent?  Any legal or risk to allowing them in before the effective date on the lease?  Thanks in advance for the comments and welcome any other additional issues I might not be considering!