DF's best friend and his fiance are planning to surprise him by coming to our destination wedding. They plan on showing up unannounced (to him) at our rehearsal dinner the night before the ceremony. What he still won't know is that his friend's fiance is going to be my MOH. Now his friend is thinking about surprising him further by walking down the aisle as a groomsman. Right now our bridal party consists of DF's brother and my surprise MOH. DF thinks my brother is standing up as my "maid of honor". If his friend ends up in the bridal party, my brother will be on my side. However, after finding out the price of renting a tux, he wants to wear his dress blues (he's a marine). I think it would be tacky for a groomsman to be in blues while everyone else is in a black tux... But I don't want to hurt his feelings and tell him no because I don't think he can afford the rental... What do I do??? What would YOU do?