This is not great. I know there are controls in place to stop chain voting, but if it only takes 5 votes in 5 minutes to reach number 1 then the system is wide open to abuse.
Most systems are vulnerable if you poke around a bit. In my experience the HN voting ring detector is pretty wily.
That I agree with :)
The problem is that no system can detect signal in five votes. The numbers are just too small to be significant.