#2. "Are you sure you can't let me look at such-and-such book on the Hold Shelf for a few minutes? I just want to make a photocopy of it."
This is a double-whammy here. At most libraries the Hold Shelf is considered to be inviolate -- any book on hold for a patron is as if it has already been checked out to that individual, and just as we wouldn't come sneaking into that person's house to let another person take a peek at the book, under normal circumstances we don't let others use that book even though it's ten paces away.
The more egregious part of this question, however, is the bit about photocopying the book. Major copyright violation. Ever since the advent of copiers in the library stacks, publishers have been a bug up our profession's collective butt concerning lost profits resulting from all the illegal photocopying going on right under our noses (in case you didn't know, yes, it's illegal to copy an entire book, or even more than a single chapter!).
After much wrangling back and forth between our lawyers and theirs it was agreed that by posting all manners of warnings in the stacks, on and around the copiers, and in the basic library use guidelines which every prospective library user must theoretically read and agree to abide by, the library absolved itself of its legal responsibilities -- except when confronted with obvious evidence that a patron intends to violate copyright law, such as the above question, or a document delivery request for a "clear copy" so that it can be reproduced for a presentation or hand-out. At which point we are legally obligated not to help you.
So now you know. And knowing is half the the battle...
(This is also why most public library photocopiers don't have document feeders!)