This is how my first silent/sealed bid auction went down. About 15 minutes prior, the facility manager gave everyone (about 12 buyers) about 12 sheets of papers with the unit #s, as well as your point of contact. At auction time, each one of us got into 2 15-passenger vans and then headed out onto the lot, which had both indoor and outdoor units. The manager's staff showed each of the units, which we were only able to see at the door without touching. Of course, with each unit came a bid, if you wanted to. One outside unit even had bidding on a car!
After showing the 12th, all of the buyers headed back to the facility headquarters, where with whatever we bidded on, placed within a manilla envelope that we had to seal. The manager, as well as her staff, said that if we won, she would call us.
Sure enough, about 15 minutes later, I received the call on the unit that I bid on. When I returned to the facility, the manager still had 12 stacks of papers with everyone's bid on it. Out of curiousity, I asked on how many people bid on my unit, and she just counted the sheets of papers and said "3" besides yourself, without divulging who bid on it and what.
Kinda thought it was a neat and fair process, being my first time at a silent/sealed bid.