I was fortunate to be able to attend the once in 4 years international event like WCD. It was held in the COEX, the venue of class. To walk from one exhibition area to the other end might take one 10 minutes. Imagine how vast the place is.
What's more, for a start, we went hunting for freebies. There were almost 1000 exhibitor booths, probably one won't be able to finish in one day.
So, we selectively went to the booths with long queuing lines, indicating nice goodies to be collected.