Subtle difference between standard instances

We, at Anygma, noticed that a and b below have different behavior: a, b :: (Int->Int) -> (Int,Int) -> (Int,Int) a = fmap b = second See the blog post at http://netsuperbrain.com/blog/?p=74. The standard instances for Functor, Monad, and Applicative for tuples is strict. The Arrow on (->) when applied to tuples with first and second, however is non-strict. It is a subtle discrepancy, but it does make a difference for FRP when deriving these standard instances. Any objections to making the Functor, Monad, and Applicative instances for tuples non-strict like Arrows? David