The Lunatic said:
A lot of people do not recognize transgendered people and so do not feel comfortable sleeping with them.
And I don't want any innocent trans people to sleep with horrible bigots, so I quite agree that any people who feel that way should try to stay as far away as possible from any trans people they might be tempted to sleep with, and preferably as far away as possible from any normal human society where they might inflict their bigotry on innocent people.
For the rest of humanity, look. I've had friends (not heterosexual friends, because as mentioned that doesn't happen) who have actually been in this situation. If you think you're attracted to someone, but then when they get naked you find you're not attracted to them any more and don't want to go through with it, then just handle that like an adult. Don't do anything you don't want to do, and don't deliberately hurt anyone.
The Lunatic said:
There are a few places that have laws on matter concerning consent after the fact. Rape by deception is the umbrella term it comes under, and cases such as R ? v ? McNally have specifically covered deception on gender and so on.
So, here's the thing.
* McNally is not trans. She does not identify as or present as a man. There were suggestions during the trial that she may have some kind of confusion about her gender identity, but these could never be substantiated, which hurt her case because it meant (if the account given was true) her primary purpose in presenting as a man was not the expression of her authentic gender identity, but her desire to persuade an (apparently) straight woman to have sex with her. That matters.
* McNally pleaded guilty. It's completely unclear why she did this, although she later claimed she "just wanted it to be over". She also seems to have been deeply confused about court procedure and the burden of proof. Actually, without this guilty plea, there really is no prosecution case. In fact, there is significant evidence to question the prosecution's version of events, and the case remains extremely controversial both for sowing myths about the law and trans people (as you're trying to do here) and for the questions it raises over whether McNally was adequately supported by her own legal counsel.
Like, don't get me wrong, it's shitty that such a thing even exists on the statute, but I really wouldn't read into it. Heck, it was partly overturned almost immediately, with the sentence being dramatically reduced.
The Lunatic said:
Ultimately, you have a right to privacy with your trans status, but there's obviously a degree of trust that must come with sexual relations in which deception of any kind is not acceptable.
Deception of almost any kind is acceptable. I mean, let me quote from your own link:
Mr Wainwright argues that deception as to gender cannot vitiate consent; in the same way deception as to age, marital status, wealth or, following EB, HIV status being deceptions as to qualities or attributes cannot vitiate consent.
You can, under existing British law, lie about your age. You can lie about whether you are married. You can claim to be a billionaire. You can even (in some cases) lie about having a permanent and life-affecting sexually transited disease. Rape by deception applies to an incredibly limited range of situations pertaining to actual acts which occur in the bedroom. The law is not there to legislate trust.