TDI fanfiction: julie TDIpod

On some episodes, people won invinciblity and didn't even use it. Like on "That's off the chain," Heather won invincibility and didn't use it, because Chris eliminated Lindsay for crossing the line last. On "Hook, Line, and Screamer," Gwen won invincibilty and didn't use it because Chris eliminated DJ for not confronting the killer, and still chickening out. The same is on some other episodes (i can't remeber all of them.) Maybe Chris had to give out a invincibilty. But what's the point of doing it if the camper won't be able to use it? Some things in TDI i don't get.