"It happened routinely, especially later at night when the patrons were inebriated. However, you could usually expect a better tip from the drunk bowlers, especially if you would "help them along" by discreetly knocking over a few extra pins. We would occasionally taunt them and quickly jump over the safety wall as the ball was approaching.
One of only a handful remaining, there is still a public manual alley in Shohola, PA at Rohman's Hotel, It is cheap (1$ per frame) if you set your own pins or bring you own pin boy, (or girl)." - internet, Tom Gibson, 30 Nov 2007.