I agree, but ironically enough, the hobgoblin warrior respawning on raft glitch actually helps even this out. Even if I can't get 31 stars because of river glitchers, I'm still able to kill a couple respawning on my raft and I'll still make it most of the time. =D
They can be a bit annoying when you're trying to aim crash shot though. But nothing a good crit wm doesn't solve