pulled the battery out and reset?

dunno about you but since moving to the 50D im forever rolling my thumb onto the AF-ON button

Different model, manufacturer etc but my K10D has only crapped out on me because of the cold once, and that was the battery not liking -10C in Paris last year. Id expect a camera on the 7Ds level to be at least as resiliant to the cold as my K10. Id have thought the weather sealing would mitigate against moisture in the switch. Of course it could be defective.

Is it possible that with gloves on you pressed a button without realising?

I presume the 7D is above such silly gimicks as the doohicky which detects you putting it to your eye which some of the Sonys have? IIRC that can be set to trigger AF.

Hmm, I was stalking the (avian) birds today, and encountered the problem again. This time the centre focus point was lit up and focusing as if I just had spot focusing on. Bit annoying as its the first time Ive got tits in the frame.

However a bit of fiddling and it seems that a certain method of selecting the focus points might have fixed things.

Basically on the 7D there are at least 2 different ways to choose the focus points (probably more). Theres a quick menu button you can press which brings options up on the LCD, and you can choose through that way, which is what I was doing. You can also press a button and then the m-Fn button whilst looking through the viewfinder which cycles through the options. The quick button method did nothing when I was in the field, but just by pressing the focus point button and then m-fn to cycle through the options once seems to have cleared the lock.

So maybe I am pressing random combos (99% sure I didnt) whilst moving the camera, or perhaps the camera getting cold too quickly is doing something inside. Ill keep my eye on it, hopefully will end up out in the forest in the next week sometime