I accused someone of this once without even knowing if it was actually a real thing or not. It was one of maybe like 5 times I ever openly accused someone of cheating in 8 years of playing this game.
The Zarya kept bubbling herself or a teammate exactly 1ms before I did any form of cc, ult, or heavy damage to them with superhuman reaction time. After the 5th or so time it happened I decided it couldn’t be neither skill nor luck. Good to know I was right.