You can't tell the difference, they are identical, but not the same. In the same way I could have a perfect cube of carbon in front of me, and then duplicate it so I have two identical cubes of carbon. Now send one to Mars on a space ship, we now have two identical cubes of carbon, one on earth, one on Mars. They are not the same cube though are they?
No, but if anyone's saying they're the same (I might even have done that previously), it's an informal shorthand for being identical.
The survivors of your two experiments can't tell the difference, that does not change the fact that the guy who steps into the transporter in scenario 1 is now dead.
Identical but not the same. do you get what I mean? I'm not sure I'm being clear.
There might be a problem with terminology here. The original collection of cells we think of as a person is no longer grouped in such a way as to warrant that title. We're in agreement on that point. But if a different set of cells are created/arranged/reanimated in exactly the same way somewhere else, we need to be very careful about what we're saying, because it depends on what makes us "us". Who was the guy you're saying got killed?
If you're a materialist, you believe (or ought to) that consciousness and our sense of self is an emergent property of neural function, which leads naturally to the conclusion that the "copy" would be as much you as the "real" you. You don't have to like that or feel comfortable with it (you may well have the same reaction as Nick227 that it feels wrong, even while admitting that there's no rational basis for that feeling), but it's the logical result of your beliefs. If you're not a materialist, of course, none of this applies.
It's not something I'd do for fun, and if I look at it the wrong way, it gives me the squicks, but if I'm interested in preserving "me", what does that mean? Would I still be "me" if I was a Futurama-style brain in a jar? If my thought process were stored in a computer? We're back to the mad scientist experiment mentioned earlier - would you rather provide the body or the brain, given the choice? I'd say brain every time.
I think the sticking point here is that we all have a sense (or illusion) of continuous consciousness, and for obvious evolutionary and survival reasons that sense of self is bound up with the meat puppet we call "us". Our instinctive understanding, which has served us very well, is that if you destroy the body, you destroy "us", so the idea of destroying that body to be recreated somewhere else appals us. But if you'd choose to be the brain for the mad scientist's new creation, I don't think you really believe that.
I understand. Really. There's a part of me, even as I'm typing this, that thinks the result of going through a transporter would be that I die, and someone else is created who just thinks he's me. He'd be me to all intents and purposes, but the "real" me would be dead. Because my instinct is to associate my identity with my bodily existence and apparently continuous consciousness, so I see the fate of the original as my fate. But rationally, I don't believe that. I believe if the concept of "me" means anything, it's something that can be maintained by a transporter. "My" thought patterns would still be the same, and even in an identical body, so "I" would still exist, even more so than if my thoughts were saved to a hard drive.
(In the unlikely event that transporters like this are ever invented, I predict that people will get over these worries pretty quickly, not just because it starts to seem normal, but because every time you go through one, the person who steps out would be the one who "survived". After a few trips, that would breed a massive amount of complacency.)