I would disagree with not reading what they wrote. Ideally they're submitting online via whatever online system the schools you're applying to use (SOPHAS, the school's one, etc) and they (the recommender) will give you a copy. It's perfectly ok to ask for a copy of their recc before asking them to submit online. Unless you know them extremely well and know they right excellant LORs, I think seeing a copy beforehand just makes good sense. I've had recommenders even offer this because they want to write something good for you and sometimes are open to your feedback.