The players put the robot on the field. The referees should never ever touch your robot. If they want it moved they will tell you.

You can use the limit switches pretty much any way you want to and be totally within the rules.
Also don't forget that you have the left/right/enter buttons and the graphical LCD on the NXT. There are alot ROBOTC of examples of how to do this.

I'm glad the light sensor has enough resolution for you. I'm actually a bit surprised as blue/red are normally very close, but maybe since the light sensor uses a RED led its enough to make a difference.

You might be able to pickup even more of a difference if you use a red light filter (one of the eyes from those cheap 3d glasses might work)

They've always said in the rules that this was legal...I've always wondered if it actually works.

You are the ones who put the robot on the field but you have to work out with your partners who starts where. It would be legal to use such switches as long as you use legal parts, either lego, like we have done, or parts from the Tetrix kit.

I would not recommend the use of the standard light sensor because it is, even with the LED, slightly dependent on the ambient lighting, so be wary when you code such a sensor and test for a range of values rather than just a single value.