I think Laura wants to leave surprises for the presentation and she already has a lot of things to be stressed about come thursday. While the event will be fun for us, she will probably be very nervous at every announcement or lack of in regards to her leaks.
Also one thing that i want to note is that while GAF is generally respectful towards the leakers, even when they are wrong, people can be really nasty, especially if you are transgender or a woman. So Laura gets a lot of transphobic comments every time she leaks something, and Emily receives a lot of abuse too. I think this only adds to their stress.