Being an American I used to attended many "shot of beer" festivals here. I don't bother any more. A 1 or 2 ounce sample does not tell me if I will like a beer over the long haule. At these festivals I found my self constantly on my feet going from line to line (or as you all would say que to que) drinking my beer from the previous line while waiting for my next "shot of beer". All the "shot of beer" festivals I attended (save one which I will explain in the next paragraph) this was the only choice you had. There was no option to order any other size measure (some festivals provided a six ounce glass with a line at 2 ounces which came in handy if you had a friend behind the bar filling it up to the brim 8>)).
In 1999 I attended the worst beer festival ever in my opinion. That was the Great American Beer Festival held in Denver, Colorado each Fall. The hall were it was held was way oversold. I was constantly standing on long lines for a shot of beer (except when I cashed in my special coupon for a full pint which was in a separate less crowded area, however each patron was entitled to only one full pint and could not purchase more). Having been to the GBBF for the first time in 1998 I saw first hand that your national festival was much superior to mine. In fact this was the next to last "shot of beer" festival I ever attended (the last one being the 2001 Chicago Real Ale Festival, which fortunately I knew someone at the bar and he kept pouring me full 6oz glasses instead of stopping at the 2oz line).
I was glad to hear from reading this thread that the GBBF was going to 1/3 pint glasses this year. This will allow for sampling of more ales than before with the half as the smallest measure. A 6-7 ounce sample to me is sufficient to getting a feel for a beer but not the "shot of beer" method used predominately here in the USA.
Cheers, Bruce CAMRA member from New Jersey
P.S. I forgot to mention that Denver is a great beer town. Many excellent brew pubs. I just wouldn't waste my time going there during the GABF when many hotels are fully booked. Better to go there at another time.