Scratches? Does movement need to be removed to polish caseback?

[mjr24]

I am looking at a watch that has some minor hairline marks, scratches, etc. on the case back.

Two things....
1-I can't say I've ever had any scratches on the case backs of any of my watches. Why would a watch have markings there?

2-I do remember when I went to have my Breitling polished at the AD, they claimed they could not polish the case, at all, without removing the movement....and that basically it had to be sent to Breitling to do this (because you could mess up the movement otherwise). They had no issues polishing the bracelet. I had multiple AD's tell me this same thing.....I asked around (as I had never heard that before....about having to remove the movement). Now, for what it's worth....I had a see-through caseback on my Breitling Navitimer....not sure if this had anything to do with it.

3-Is this something I need to worry about on polishing the caseback of a Rolex (is there a chance of messing up the movement)?