ETF chatter

I read something about the oil etf and how it scheduled it's rollover of it's contracts, and the oil traders have started gaming them.

with the interesting divergence of the leveraged etf's, If I worked for a big trading firm... I would be working out ways to exploit that divergence. If there is a predictable divergence, it can be gamed.

all of this is continuing to make me nervous about all the ETF's..