Why is that?
Is there some adhesive that's hard to replace or is the dome sheet easily damaged in the process? Or is there some other problem?

Here at 1:52 [1] it looks not trivial but quite doable to remove the dome sheet. However the next slide in the video says: "Do not use the domesheet again."
I'd like to understand the reason.

Of course reassembly might be a completely different story than disassembly which is why I usually don't like disassembly guides that end by simply stating: "to reassemble just follow these steps in reverse order."


[1] http://www.youtube.com/watch?v=hA82LYF64es