I'm being a pedant but: Black tie and tails event? Tails are normally worn with white tie. Double check the invite: you don't want to end up at a gun fight with a knife - to paraphrase Sir Sean.

Throw away the ruche or lock it in a bottom drawer and save it for one of those evenings when everyone has gone out, you can lock the door, draw the curtains.... and indulge yourself a little.