Killing your date glitch
Usually Niko can scare his dates but cannot kill them. When on a date with someone, have them follow you to any coastline. Then, swim out into the middle of the ocean. Once you go a few yards in the water, Niko's date will instantly die. Note: This glitches the game. If Kate gets killed, her telephone will always be busy when called. Niko will also receive date invitations from dead people labeled as "Unknown Caller".