The OP asked about halter & showmanship.While yes I have seen ribbons on riders i have yet to see one on a horse in hand. I personally would not be showing a known kicker
. That said if you are going to go ahead anyway.. showing halter remove yourself from any crowded hitching rings & go in just as your class is called.Be watchful of your competitors,tell them to keep there distance/out of your space as your horse is known to kick.As a fellow exhibitor I would appreciate the warning.In halter you generally line up head to tail so ensure the horse behind you keeps its distance.Besides watching for your fellow exhibitors you should be ever attentive to your horse & his/her non verbals & assure there attention is always on you.
In showmanship you are exhibiting the horse alone in the ring doing a pattern so at that point other horses shouldn't be an issue just in line up after awaiting placings.
When I showed showmanship my coach always said when she has that chain on she is at work until you let her know she can relax & chill.Any movement on my part was a cue for her,her focus was always on me.A horse that is working should do just that & have their attention on you.If you let your guard down & allow them to do there thing or give them mix signals that is when they will do what comes to them & often not what you want
or your fellow exhibitors especially when it comes in the form of kicking.
I do remember being in a crowded hitching ring awaiting halter class.There was this one mare that the handler had her as seperated from the others the best he could in the crowded environment,he had no problem telling people to mind her space as she was moody/in heat & may lash out.He was mindful of her demenor & had no problem telling people to mind her space & people respected that.
As for the ribbon in the tail I think many judges would count that warning of a vice & look down on it as far as placing goes,particularily in showmanship!!
Too many things against you IMO,#1 the welfare of your fellow exhibitors & their horse & if you choose to go the ribbon route I think that won't win any impressions with judges either.Another thing to think about,A riding horse that kicks out another horse is generally going to take the blow... an in hand class if your horse kicks out there is even more risk that a person will be one that is in the line of fire.
IMO For the sake of all involved,leaving your horse at home is the best idea....