I am positive that it is not to drive the cost up!!! I just started flying pattern this year. I have flown two D2 contests. I currently fly an Eflite Splendor. This is by far the smallest plane sitting on the line by almost 20"s. It flies extremely well and costs a fraction of the price. Obviously its well under weight. So you really don't need to spend Thousands of dollars to have fun and be competitive.

However as you have already mentioned a lighter plane performs much better. But in some cases it does not fly nearly as well as a heavy plane. Seeing as your from Hawaii I am sure you know all about the wind factor.

I think as long as you do not plan on going to Nats or at worlds I would say most regional events do not weigh planes.

Just go out have fun, meet people and become the best pilot you can.