Would you tell the lesbian that you're in love with her?

A frequent topic of conversation between me and a certain friend of mine is confessions of love/romantic interest to friends. Most recently this came up in the context of Kevin Smith's movie Chasing Amy. My friend asked me if I thought that Holden had done the right thing when he confessed his love for Alyssa. The implication, which she later spelled out, was that he had. My response was that, given the way the movie works out, he did the right thing. However, I don't think that it would be the right move in every situation. One of the main issues is the question of honesty versus civility. Is it better to be honest with a friend, even at the potential cost of hurting him/her, or damaging the relationship? Her claim is that it is always better to take the risk, because you never know what the result will be, and if it pays off, it pays off big. Now, I disagree. Sometimes one can be certain what the result will be, or that the consequences of failure aren't worth the chances of success. In the end we both agree that the decision should be based on a risk/reward analysis. She just thinks that the risk is always worth the potential reward. I don't. Sometimes I want to have a girl in my life so badly that it isn't worth potentially alienating her for the slim chance of something better. A thought just occured to me. If I follow this line through to it's logical conclusion, would I only ever make a move on girls I like less, and never end up with the girls I really like? I don't think so, but I'm not sure why. Any thoughts?


UPDATE: My friend E-mailed me with a clarification of her position. Apparently, she wanted to comment, but there is a problem with the comments section of this post. I'll try to fix that, but in the meantime, here are her comments.
I would like to clarify my position in response to your post. If you are 100% sure that telling her would hurt her far more than it would help you then by no means tell her. For instance, madly crushing on a happily married woman is never a good idea. However, with that said, if you like your friend so much that you can’t get her out of your mind and you’re not functioning properly then in most cases I think that the risk is always worth the potential reward. For if she is truly a good friend of yours then the risk of telling her will not be that large. It may be awkward for a little while but she will in no way alienate you from her life. If, in fact, she does then clearly she was not that good of a friend to begin with.

Note to self: One day I promise to take my own advice.

Sincerely,
Your Anonymous Friend (She actually signed it this way.)

UPDATE 2: The comments section is fixed.