No? Wow, does anyone commenting actually have any experience with this?
Both North American and the Indo/Aussie crayfish are great tankmates for Africans, especially with Mbuna. The cichlids can't hurt the crays, and are too fast and alert to end up as lunch. The large amount of food going into most African tanks means the crays get lots to eat and, since they are opportunistic feeders, don't even try eting the cichlids. The large amount of rock work gives the crays ample places to hide when they are shedding too. I've even had the crayfish breed in African tanks.
We keep our crayfish at the store entirely in the cichlid section, it's the only area where they don't eat the fish. I've personally done it at home too.