Seriously. This is a non issue.
Several cellphones have come with filtering enabled by default for years and years. It's not a big deal, you just call them up and say "Yeah when I bought this phone, I wanted to use the internet. So disable your crappy little filter, and we'll say no more about it"
Some ISPs are, apparently, asking for explicit confirmation with a phrase such as "So you are requesting access to sites that carry pornographical material", and if you want to access anything that the Government has decided to block, you must reply "Yes."
I have no doubt that lists of people who have opted-out will, at some point, be leaked.
Source: Am in the UK & have opted out of filtering. All fixed line ISPs allow toggling the filter bias their online control panel, or by clicking a button when signing up online. Mobile ISPs vary - O2 mobile require you give your card details.