Only one time did I go to an auction and they wouldn't let me look. But it was an open house to look at the property, and they had piled the personal property in closets and hallways. I could see quilts, and asked if I could look at them. They told me no. I didn't go back for the actual auction.
Around here, everyone shows up early and paws through the boxes to see if there is anything worth staying for. I'd leave, too, if they didn't let me look. In fact, usually the ads say "inspection starts at 9:00 a.m.) or whatever.