<p>“Technically, having sex w/ her would be illegal but you wouldn’t get prosecuted because you were under the false pretense that she was of age.”</p>
<p>That depends. I believe everywhere (and certainly almost everywhere, but I don’t know if there’s one or two states where this isn’t the case) you could potentially be prosecuted, whether you had any reason to believe she (or he) was under the age of consent. Whether or not you actually get prosecuted in that situation… That depends.</p>