Most certainly. Some leasing locations will include a certain amount of gas and/or oil with the vehicle under certain maintenance programs, but not always. This depends on the lease.
It's really up to each landlord if they want to include gas and oil in a lease, but I believe that you shouldn't because every person uses a different amount.
Leases for cars are agreements that can vary between parties. Some include gas and oil costs, others don't. Whether the terms in yours should depends on whether you and the other party agree to do so.
Yes, it is important that the consumer is aware of what type of gas and oil are used in the vehicle. Especially since gas and oil of poor quality could hurt the vehicles performance.