Happened to me once, in the early 1990s, on a BA 767 departing IAD. We were 20 to 30 seconds into the takeoff roll and creeping up toward V1 when the crew threw both engines into idle and stood on the brakes. We were told they had a warning light related to the thrust reversers. As this was a short time after the Lauda Air 767 loss traced to a thrust reverser deploying in flight, we were quite happy to return to the gate for inspection. We took off about three hours late, but uneventfully.