If you offer two sides, often the meat gets hit very hard and the sides do not. The exception being mac-n-cheese. Most of the times that I have done tri-tip and chicken, I have been asked to provide beans, salsa and slaw. I end up with lots of beans and slaw, and people asking about more meat.
If there is a table with several sides, then people tend to fill up a little more mindlessly, especially if there are things like little sausages, potato salad, mac-n-cheese etc...you can then use less meat. If I am starting a meal off, I like to throw smoked sausage and chips and salsa out there, start filling people a bit. If you just do two sides and meat, people really chow on the meat, often completely ignoring the beans.
I'm feeling bearish, and I'm packing a Wusthof Grand Brisket slicer from MABA
"perhaps...but then again...maybe not..."