I buy property at the foreclosure sales, called Sheriff Sales here, often. Sometimes we get inside, sometimes not. We look at the properties before the sale, we do not drive around from property to property during the sale. If we did that we would miss much of the sale. Soemtimes the foreclsoure list is 100s of properties and the Sheriff sells them very quickly.
From the original published list, about 1/3 get postponed, sometimes for seemingly no reason. There is an abondoned house that I used to own 3 owners ago that is on the Sheriff list. It is vacant for 2 years now and the owners have split and probably haven't paid their mortgage for probably 4 years, but the sale keeps getting postponed, and its not even owned by the bank yet.
Another 1/3 get cancelled. The owners sell their property, sometimes short sale, or they bring the delinquency current or something else happens to fully cancel the sale.
Of the remaining 1/3 most start at a price too high to be economical and end up as bank owned REOs. Particularly houses with mortgage guarentees like FHA and VA. The banks don't discount the prices and get their guarentee money. Of this remaining 1/3 about 10% to20% are sold to third parties.
I've bought houses at the sheriff sale and even bought an entire subdivision at sheriff sale.