Until recently, anytime I clicked on 'buy' on the itunes store, I had to sign in with my Apple ID and password. However, recently when you click on 'buy' it immediately starts to download the item without asking you to sign in. Is there any way to stop this? I'd much rather be prompted to sign in each time I buy something. The touch sensitive trackpad on the mac doesn't help, as it has resulted in me downloading things I didn't want as I scrolled up and down the screen.