I've been practicing for the October LSAT for a couple months already. I just picked up the 2004-05 LSAT/LSDAS Registration and Information Book from my university's undergrad pre-law advising office. I was shocked to read the following regulation:
"You may use only a No. 2 pencil or highlighter pen to underline passages in the test book. Ink or ballpoint pens are not permitted."
Are pens really prohibitted? I had been using 4 or 5 pages of scratch paper on the games sections until I found out that was prohibited. I managed to adjust by using a pen to make an initial diagram for each game problem, then using pencil to fill in specific details/conditions and quickly erasing for each question. This technique has dramatically boosted my scores, because I spend less time redrawing diagrams. I can't imagine why they would prohibit pens during the test, unless to prevent exactly this technique.
First no scratch paper, then this. I'm afraid to find out what my next surprise will be - Does the writing sample have to be done left handed?