All mining pools are, and have always been, vulnerable to block withholding attacks.

These attacks are rare though. There were those guys mining at BTC Guild and Eligius who had a programming error in their software, having to do with how they determined whether work was above or below pool difficulty. I also read on Reddit someone claiming to be block withholding on Ghash on purpose. Those are the only cases I've heard about so far.

The real solution would be to get protection against block withholding in the next Bitcoin hardfork. Other than that, pool operators have to watch users with suspiciously bad luck. Accusing everyone with slightly bad luck is not a solution. I don't see it as a solution to stop pooled mining either, and have everyone solo mine. For most miners solo mining is not an option.

There's no reason to believe mining chips would do block withholding. That would actually require more logic on the chips.