Questions of faith must not have a necessary outcome. True questions of faith do not let natural suspicions slide into fixed disbelief. Instead, they pivot the course of life. Therefore when faith truly becomes an issue, there must be doubt about a personally formed issue. In the examples of parental infallibility, Santa Claus, etc. . . there was only blind faith to begin with.
Blind faith is no faith at all.
In order for faith to be called into question, a true faith must have previously existed. The root of the question, therefore, asks what faiths have truly formed. To answer this question, I might point to a romantic example. A belief in unending love with another person formed, and this was broken. This belief was not assumed, but grew out of life experience.