I don't think that they have a problem with that. When i took the exam they gave me scratch paper when I first entered and I could have used it however I liked. I also remember a student in the kaplan class I took asked the same question and the kaplan instructer said that you can hold up a paper to the screen in you like.
Hmm not sure, but usually the test center gives you the paper and as long as you give it back to them, then they have no qualms. Plus many people are in there taking various tests from a broad spectrum of fields. Dont worry too much about it!