Is EMI protection really necessary?

So this is the first time I've done anything like this. I thought the kit I bought would come with everything I need but hey it's the internet. It's hard to tell what will come with kits and what won't. So my phone had some water damage. Lines appeared on screen and rice didn't help either. So I bought this: http://www.amazon.com/gp/product/B01188M...

It came with everything, except I completely forgot about this wire mesh-like tape thats across the bottom circuit stuff. I think it's called EMI tape? Does anyone know where to get it? Is it absolutely necessary to have? I've been trying to take it off the old frame, but it keeps ripping and i don't want to completely destroy it. I want to get this done as soon as possible so any help would be absolutely wonderful. Let me know if I need to give more information, or pictures.