It would seem that the lease allows one parking space. Whether or not the tenant has a car, she gets a space, as you mentioned, for her own “Lessee’s private passenger vehicle.” Therefore, according to the lease, she is entitled to a spot. The problem with enforcing this kind of wording in a lease is that you would have to prove that parking another vehicle in that space, her guest or someone else’s car, impacts on your right or enjoyment as a landlord. Or that it impacts the rights or enjoyment of another tenant in the building.