Hi there, here's what I've been wondering about.
Just today I received my Xperia Arc back unchanged with the reason that the Orignal Software was changed and that therefore the warranty faded. Now I did this before, just as I did it this time, with wiping my phone completely and reflashing the 2.3.2 original firmware on it with flashtool. Now here's the question: How can they still know that it was rooted? I've not done a lot differently from last time and still this time they wouldn't replace my phone.