There is no such thing as a risk free trade. The trade you speak of is essentially an interest rate trade, and if interest rates change you could be at risk. Also, you will also be dealing with a wider bid offer spread and extra commissions for a trade that could be effected in a simpler fashion.
As always: Trading in futures and options is very high risk investing. You can lose all or more of the money you invest. Only risk capital should be used.