In reply to Tall Clare:
> I think it's more that I'm baffled as to why anyone would *want* to proof fleece...
To make it water repellent...?
Which can mean that you don't need to wear a shell layer in mist or light drizzle (DWR'd Ultrafleece/K2/Karisma works quite well like this, as do microfibre fleeces). Or mean that it takes longer for the fleece to saturate, and quicker to dry when it does.
The only garment I wouldn't consider applying a DWR treatment to are wicking base layers. In an ideal layering system, a wicking base layer spreads sweat over its surface, and allows it to evaporate, and the resulting water vapour passes through the open structure of a fleece, and out through a breathable shell. Ideally, we don't want the fleece to wick and absorb lots of water, as that would be heavy, reduce the dead air space, and provide a reservoir of water that will chill you when you stop moving.