Open day 20/09- is it possible to go into talks that you haven't booked

I've booked onto the open day on the 20th of September (I know I've booked on late), but not all the speeches that I need to visit are available. I was just wondering if anyone has been to a Warwick open day and managed to get into talks they didn't book onto? Is it easy to just wing it and get in without having specifically booked that speech?

There will be two queues by the doors to the talks - one for people who have booked and one for those that haven't. Once all those that have booked have been let in, if there are any seats left, then those in the non-booked queue will be let in on a first-come-first-served-basis