50 shifts is pretty crazy. But who knows, maybe you need it for blocking hostile uber-rituals.
That gives me an idea: a closet, somewhere in the White Council HQ, with the mother of all wards on it. When the Council knows someone is gonna launch a killing ritual at you, they shove you in the closet.
But that aside, you mostly need big Wards for stopping other spellcasters and people with Mythic Strength. As a GM I went through a 12 shift-ward and then a 16-shift ward in pretty short order a little while ago, so I can see a good argument for going up to 30 shifts.