LSE open day without booking

I signed up to LSE’s email listing in january hut they never emailed me that they had opened bookings ?? Fast forward and I plan to
go next week since london isn’t too far and some people on the internet say you can get in without a pass? They seem pretty strict on their website? Can i just show up? Does anyone have a spare pass that i may be able to re-use or if they aren't going?