yep-as much as i hate to say it, dta is right. U definitely reserve the right to ask your potential recommender whether it would be worth ur while (and theirs) to get a recommendation from them. Some recommenders may ask you to write the letter yourself, and give it to them to review, make necessary changes, and send. But schools want to rest assured that the person writing the reccomendation is being candid, and not holding anything back. This is necessary in order to get a reliable assessment of your character/work ethic/academic performance etc. If schools knew that LORs would be proofed by the recommendee beforehand, they would expect to receive biased reports which would pretty much render the whole process useless since essentially, a filter would be instituted. If ur unsure about whether a specific person is going to write a glowing report or not-you may be asking the wrong person. They want people who know you, and who have had ample opportunity to assess you, not just someone with a title. If ur not sure about them, ask. If they're not sure about u, find someone who is.