I had one direct walk out in 8 years.
That was on a day when I knew I was absolutely spot on, couldn't have faulted me, ok might have been a pound or two less than my last photos, but I knew I was on excellent form that day, not a hair out of place and my property was tip top.
There was a clue when the man made the booking, he really 'barked' at me, I put it down to his mannerisms and possible nerves. He arrived wearing shades (sunny day), fiddling with his phone, hardly looked at me before turning around and shooting off.
Not a clue what that was about.