[Kevin Sevcik]

I think the point was that the rules as stated are an engineering constraint over the entire system, not just what you have on the field at any particular moment. Since this year's rules mandate weighing all attachments together, they are probably meant in this sense. The old modular rules were meant in your particular sense.

To better detail the analogy, NASA is asking for a system for astronauts to use in space to accomplish all these tasks. You wouldn't send them without one of the attachments, because then you'd never use it.

To me common sense dictates that "spare" parts are there to be swapped out when something is broken, worn out, scratched, etc. The reason that the second motor is no longer a spare is the fact that it's not being swapped out because it's already there bolted down and integrated to the assembly. No work is being done to swap it out, you're just using semantics and pretending it's being swapped for the other part without actually doing anything. So I guess my definition of a spare part includes the physical act of replacing something.