Yes,
And the only reason I could think of is that people might think that the round is too powerful for cilvilian use and their affraid that someone might choose to stop their limo or snipe them at 1 mile range.
Last I looked into it, they weren't illegal here as long as they didn't hold more then 10 rounds in semi auto form.
Years ago a friend of mine was talking about sharing the cost on buying a .50cal but while fun idea only place we wouild of been able to shoot it at a good distance was a private range 2 hours drive north. But back then it was all way over our budgets.
...-Gixer