There is 2 different shows, wedding shows and hotels show.
Wedding shows: BS will pester you for sale. To be exact they won't let you go. After a couple of trial, we learnt smth, be firm. Say no if you are not interested in their photograph or gown. Think about it, even they provide you an unbelievable price for those, you would like it either.
our experience is that we can sit there for an hr plus to listen to them and get so unhappy about it.
Hotel Shows: no worries, they would. They are standing around while you view the ballroom setup, ROM setup and even bridal suite. If you are interested, there is normally a room where you can go in and approach them to find out more about the price, perks and date available and what they can provide. Normally you need to queue for a while.
It is best to go for hotel shows and avoid wedding shows for BS unless you have any BS in mind that you would like to visit. Shows normally give you more perks.