Currently, public sub counts are abbreviated in most but not all places across YouTube. In August, we’ll make this more consistent by always showing abbreviated sub counts publicly. Creators: You’ll still see your full sub count in Studio! Learn more → http://yt.be/help/abbrev-count …pic.twitter.com/pmaKk4EU4k
You should leave ONE area where anyone can visit just to see the actual number. Like in their ABOUT tab. Anywhere else, fine. Just don't touch that one.