This is a big deal, and other funds are taking similar measures. As I've posted previously, pension funds do well out of stock-lending in the short term, as it is an extra source of income. But there's always been a question over whether it's counter-productive over the long term. The fact that BT/Hermes, CalPERS, ABP etc are all taking a similar line is a pretty significant signal that major market participants don't accept - at least for the time being - that shorting has no downside.
One could read into these decisions the idea that the regulators may have tapped them on the shoulder and quietly asked them to have a rethink. The fact that they have all only applied the bar to financial stocks might appear significant, as it matches the move by the FSA for example, but it's also common sense really isn't it? I have no inside track here, but it's possible something is going on behind the scenes (though the fact that PGGM seems to be sticking with lending might point in the other direction).
But arguably it's more significant if the funds have reached this decision alone. Pension funds often take a long time to make major policy shifts. To give up a steady income stream because you've changed your theoretical position on how capital markets operate is quite a decision in itself. To execute it quickly too suggests a real shift in belief. Interesting times.