Suppose someone enters into an apartment lease which specifically forbids guests for staying for extended periods of time. The leasee then violates the contract by hosting a guest for an extended period of time. The issue may surface after the lease ends when the guest is questioned about previous locations they have lived in a number of circumstances (applying for jobs, their own apartment, etc).
Are there possible legal repercussions for either party (leasee, guest) for violation of this policy after the lease has ended?
Update: the state is Illinois.
Update: this is also considering the case in which the tenant pays their own utilities.