It would be funny to see how long it would take for Roy and co. to realize the halfling is now a bloodthirsty undead. My guess: a long while, considering how oblivious they can be. (See: Nale-as-Elan arc.)
How is learning "Belkar is a bloodthirsty undead" any different from their current knowledge he already is a bloodthirsty monster?
Ser Ilyn, Ser Meryn, Queen Cersei, King Joffrey, The Tickler, The Hound, Ser Amory, Polliver, Raff the Sweetling, Weese, Dunsen, Nale, Ser Gregor Clegane and Chiswyck: Winter is coming!