In Point 6 of The Rockbottum CC Plan To Fix Golf, (yes, I know we skipped Point 5, but it's taking a long time to complete) Buddy explains the Two Types of Green Speeds.

Type One is the measured speed of ball roll.  

Type Two is the speed of the green's playability.  

Some of the fastest greens have the slowest Type Two readings, due to the dreaded Ping-Pong Effect, Downhill Yip Syndrome and *Reduced Cup-ability. 

*NOTE:  During periods of increased green speeds for member tournaments, always demand a printed cup placement sheet, as tournament committees are notorious for choosing "tough" pins that prove to be extremely aggravating to the players.  If no such evidence exists during the Monday inquisition, the committee will likely claim the "golfer-hating GCS" put the cups in impossible places.

Point 6 Suggests: Help the golfer sink the putt.

In the following video, Buddy demonstrates one way to help . . . or you can just sink the hole where they can get to it, but never admit--even under duress--that it was an "easy" cup.