I knew a cis asian girl that would only date black guys... I try to think of admirers like that. That's not to say some aren't creepers, creepers are creepers whether they're admirers or not. But, I think it's best to be open with what you want. For example, if you just want to have sex, there are trans and cis girls that are okay with that. If you hide the fact that you only like someone because they're trans, then it's not a real relationship. I'm a firm believer that relationships (even purely vain and sexual ones) need to be built with expectations.
Also, no woman trans or cis likes to be lied to or played with. I'm sure the timing is tricky and it's tempting to not say anything if you don't have to, but that's the same as telling a guy you really like that you're transgender : /