I agree with the folks saying that an enthusiastic glomper isn't going to be stopped by a badge sticker. If people don't bother pausing to ask another human being's permission before grabbing them, why would they stop to look at their badge? It takes the same amount of time. Creating a whole new system with touchability tiers and color-coded stickers seems unnecessarily complicated, and very inflexible for people who wouldn't want to be on one catch-all "setting"...especially when all it
really takes to make sure somebody is okay with glomping is a polite "Can I hug you, please?"
That said, I haven't had any trouble with unwanted glomps at Kumoricon lately.
(It might have helped that I stayed far away from the vicinity of the glomp circle, but...) Although several people approached me for hugs (especially as Mom Lalonde), every one of them stopped at a friendly distance and asked if I was okay with it. I was actually really proud of the younger attendees who did this!