In this answer the following image was included which shows that control of two crossing runways are on different radio frequencies.
It seems to me that having crossing runways on different tower frequencies could lead to a runway incursion or worse, an accident, if there is any loss of controller-to-controller communication within the tower. One of the key tenants for pilots is situational awareness, and being on a different frequency means that the pilot of an aircraft receiving clearance for take-off on 12 won't know about a plane receiving clearance for take off on 22L at the same time and thus, couldn't question the clearance.
Now, I realize that it's unlikely for both 12 and 22L to be in use at the same time, but if the winds are fairly calm and to the North, it could be possible, especially if traffic was high. However, I seem to recall some discussion here about an (near?) accident that happened on crossing runways where the pilots were unable to see each other as they began their their take-off rolls.
My question is: Why would different, crossing runways be assigned to different tower frequencies since this can lead to a lack of situational awareness and potentially cause incidents?