First off there is a difference between similar designs and collaboration, for example two of the RI teams (1568 and 1350) built very similar robots despite the fact we didn't talk about design or see each others bots until day 43 (at team 69's scrimmage). This was coincidence; there are only a couple of simple and reliable designs, so you will see alot of teams that seem to have some design overlap.
http://joemenassa.com/images/robotic...s/IMG_1598.jpg
Now to the topic at hand, collaboration. If two or three teams work together and all of the hs students get to work with engineers and every one learns something then I see absolutely no problem. FIRST has not stopped collaboration because it doesn't need to, collaboration does not seem to take away from the quality of the experience of the students and mentors involved. I have worked with a couple different teams and have also had the opportunity to see how some other teams work. It is definitely possible to have two or more teams build similar robots without taking away from the experience for any one. I think that more time needs to be spent focusing on the details than on the big picture. The big picture just shows identical robots, but if you read the old posts by Karthik and the other Niagra FIRST people, or you read this year’s posts by any of the collaborating team members then I think you would have a hard time arguing that these teams did not fulfill the goals of FIRST.