Quote from 1prometheus:
"Investors need to be screened just as they screen managers"
The ideal investor is one who is on board for the longer term and not going to yank funds on the first drawdown. They are not looking to "trade managers" but rather to invest with a manager.
Investors generally overestimate their willingness to stay invested through hypothetical future drawdowns, just as managers generally overestimate their "capacity."
As to "screening" investors, that's a luxury that only managers with heat/buzz, or managers who don't really want fresh money, have.