May I understand why only wheel balancing is required and wheel alignment is not necessary?
Per experience, wheel alignment is done regularly (depending on the use of the car and road conditions) even if tires are not changed. A vehicle suspension can also be misaligned even if it is tracking straight depending on degree of the the toe in/toe out settings or camber. In the same case, a car can be aligned even if it tracking left or right due to uneven tire wear or weight on the vehicle.
Having said such, it is always a safer choice to have the suspension alignment checked when changing tires, bago na eh so check it na rin. The only times i don't do such is if my car was recently aligned (and i know my car), or the car is brand new.