Xbox Marketplace, for example, asks for payment methods to download free content (free as in never having to pay, such as demos). It says it's free, but states that you need to be "charged" to get it.
It's like:
In order to get this free product from our website, please give us a way to take money from you.
Any reason why so many sites are like this? Why can't they just ask for billing information when you actually do buy something, instead of forcing everyone to hand out excessive personal/billing info for stuff they claim is 100% free? It's like asking someone walking into a supermarket and, in order to try a free sample of food, they request a credit card to be on file or such. If it's free, why do you want a way to take money from me? I think this is poor UX in my case and sites shouldn't ask until it's necessary.
I find it to be a reason I would refuse to use services. You don't ask for money until it's time to pay.