Yeah, I don't think it's right if she's going on dates with guys who think she's a real female, then she later reveals she's not.
It's like coming out of a shop thinking you've purchased one product when in fact they've sold you something else.
There are plenty of dudes out there who have a think for trans girls (myself included), but you want to know what you're dealing with beforehand.
As people suggested above, there are plenty of sites you can meet people on that go for this sort of thing.
Oh and also - rejection is a part of life, I'm afraid. Yes it hurts, but you have to continue being brave and putting yourself out there.