I love trade-shows. But Grace is right. It's easier getting through airport security than getting into some shows..
It is however worth any effort that you put into it. Usually you can come across some new products that have not come out on the market yet and get a jump on the competition. Not everyone will be willing to deal with you depending on what your purchasing budget is. However at most shows you can usually find someone who is willing to work with you.
I have a list of every trade show in the united states with contact numbers, so I can be aware of which shows are taking place, where they are taking place, and especially when they are taking place. This gives me the oppotunity to 'pre-register'. This will save you a heap of time and trouble if you plan on going to a particular show...
Too, if you are planning to go to a show, call in advance and ask if they have set up any deals with hotels for visitors. Often the larger shows will have arranged some type of discount with several hotels while their show is taking place and this can save you some bucks...