I get freaked out to. My first Apple product, rMBP (mid 2014) bought in December 2014. I bought AppleCare with mine but still worried it's going to happen to me. I get anxious listening about this staingate. I bought my rMBP in December 2014 direct from Apple store with Yosemite preinstalled so hopefully it's recent enough that mine won't get the problem as in hopefully they sorted whatever it is that causes it.
I keep mine on my desk 24/7, it never goes out or been put in a bag or anything so hopefully that will help and at the moment it looks perfect, I use organic, all natural, chemical free Eco+ screen cleaner (made in britain) from Amazon UK. I've used it now for about 3 years on my TV and mobiles etc and only product i use and so far i've never had no ill effects, it's expensive but it does last ages and i wouldn't buy a cheap cleaning product for an expensive rMBP.
I don't like buying any kind of insurance either but the cost of a repair/replacement it's just not worth leaving the apple care out to be honest, It gives me such peace of mind (sort of) lol but can be bought much cheaper online, just do research on the seller in question and ask questions if you go down this route.