It's not illegal, but your uncle was sort of right. Wet brakes are never that good. The whole point was that he said illegal, so it doesn't matter.
Someone said, "V2 has an inversion?" I know this was awhile ago, but I'm just looking at this topic now. One out of two of them does.
If the brakes where less safe in the rain then the park would not open the ride.
--Jay