Reasons I don't put my info on my discs:
1. I find almost all my discs.
2. Discs I don't want to lose stay in the bag on risky shots over water, when getting dark, when I am playing a quick round and may not have time to look etc. Basically any disc I lose will be easily replaced. If I do somehow lose one of my favorite discs, it is still only a disc. It would suck but it isn't going to ruin my game and I'm not losing any sleep over it hoping someone will call.
3. If I can't find it myself, I had rather someone else have it.
4. Discs with ink are worth less if you decide to sell/trade them.
5. I had rather replace it than go try to arrange a time to meet someone. It can be a hassle for me and the finder.
6. I don't like putting my phone number out there for anyone to see.
7. If the finder hits someone and injures them with a disc with your info on it, and then runs off, they are going after the name on the disc.