After further thought...my stance on the honesty thing goes beyond just for her safety.
To engage in any physical act with another man, even kissing, and not revealing this beforehand is a violation. It's intentionally withholding information from someone because you know they might not be physical with you if they knew - and while it doesn't pose the same health risks, it's no different in principle than knowing you have herpes and sleeping with someone without telling them. If you're going to be physical at all with someone they have a right to have all the pertinent information. You may not see her transgender status as relevant - but many many others will, and they should be able to make that choice for themselves.
I'm sure your friend is lovely...and it's a brave thing she did, and it's sad knowing how difficult her life will be as a result. She might have some luck with bisexual men? In any case...she shouldn't resort to trickery, and it seems that she knows that. It's unsafe...and it's not fair to her potential partners.