Most people respect clergy, and for some, it's just too much of a temptation not to pretend to be one.
In September of 2017, a 19-year-old dressed as a clergyman to gain access to Milan's cathedral. His clothing didn't match the religion he claimed, so there's something to be learned. If you're going to pretend to be someone ecclesiastical, you might want to go where less pious people congregate instead of a cathedral.
Another man sat outside a church in New York and pretended to be a priest in 1995. He had more success at convincing people he was spiritual, even listening to a few confessions. The problem was that he tended to overstep his bounds by promising to perform a wedding, a baptism and an investment of a widow's savings.
It's more common to think of a man who is impersonating a clergyman as a con artist. Most research on the subject tends to end in a story of taking money from people that the fake clergy pretended to help. In reality, the impersonation tends to end in arrest.
In novels, including mine, they're usually redeemed at the end.