Let's say you were accused of copyright infringement. Let's also include that your ISP made a mistake. Their logging server had the clock wrong, or daylight savings not applied, or some other mistake. They matched up an IP to you, but they got it all wrong. they're a small ISP and they don't have much money to spend ensuring their system is correct, and there's no real incentive to make sure it is. they don't care.
You were home at the time, infact you were online chatting to your sick grandma on skype. You did not download the files you are accused of downloading.
Now, prove it wasn't you that downloaded 3 Lady Gaga albums?
Hard ask, isn't it? How do you prove you didn't? The copyright holder claims you did, the ISP claims it was you. The ISP doesn't, and shouldn't, record what you did online. How are you to prove it wasn't you?
Is the claim "it wasn't me, i didn't do it" enough? How does that hold up?
Maybe the copyright holder made it up? Maybe they just put together big giant lists of random IPs - what's the stop them doing that? They then sit back and collect the money from damages, from people in countries that have streamlined automated copyright accusations like New Zealand is in the process of doing. Move over patent trolls, here come copyright trolls.
Let's complicate it further - you're living in a student flat with 5 other students. Your flat has been accused of downloading the last episode of Lost, illegally. Everyone says they didn't do it, and you know you didn't either. What do you, the account holder do? Do you start logging everything your flat mates do? Is it any of yoru business? It's not even possible because a simple use of SSL and you have no idea what your flatmates are doing. Do you refute the accusation with "everyone living here says they didn't do it" - does that hold up through the process of notice¬ice? Does that defence work in the copyright tribunal? You have no idea if the copyright holder's agency got it wrong - or your ISP got it wrong - or if one of your flatmates is lying - maybe it's your flatmate's boyfriend who did it? When the fine arrives, who pays it? Or does the whole flat get disconnected from the internet for 6 months. Try completing your assignments without internet access.
What is the end result of this? The Creative Freedom Association asserts this is bad for copyright, as it foster bad will and dislike for artists and copyright holders. Being punished for something you didn't do and being punished for the acts of your flatmate, or a visitor, or someone you kindly shared internet with, means yet more disrespect for creative works and copyright.
How do we prove or disprove accusations? Is privacy in citizen's private communications something worth giving up for the sake of protecting copyright? I personally support artists right to own works, and the rights of those who buy copyrights from artists. I don't however value that over citizen's privacy in their own homes.