Not just corner cases, it looks like the author decided to define the question by his test cases. What happens if something outside of the test case scope is entered or desired (like possibly preventing double quotes in an address, or removing "th" from a street number like 7th -> 7). These points really should have been defined in the problem description. The ambiguity is really just turning this problem into a scavenger hunt rather than an attempt at coding.

If I want to hunt for problem/product requirements, I'll just go into work tomorrow where I do it everyday. Why waste my time with this problem.