Tetraman has it right. I should look at the intent of the rule. Although, I want to say the next few things without seeing the intended meaning:
Firstly, looking at the exact wording of the rule, “Only one opposing ALLIANCE ROBOT is allowed in the opponent’s ZONE.”
Let me rewrite that, assuming I already know I’m on the RED alliance: “Only one BLUE alliance robot is allowed in the BLUE’s zone.”
Here, it looks like the rule limits the number of offenders an alliance can have in the zone nearest their goals (if I’m not mistaken).
Also, a clarification if someone can provide it. The rule states, “A ROBOT is considered in this ZONE if any part of the ROBOT is in contact with the ZONE’s green carpet.” Where is the exact boundary of the zone? From what I have read, ‘green carpet’ does not define the boundary of the zones. This would only apply to robots that travel through the tunnel, and I assume the “boundary” is the exact center of the bump.
I would say that the GDC has chosen the green carpet because it’s a lot easier than the middle of the bump to see. After all, if you’re coming out of the tunnel, the green carpet is obvious. Ditto if you came down a bump, upright or not. The spec in 6.2.1 is that the bumps divide the zones, nothing about boundaries.
I think, in regards to your first point, that that is one of the few messups in the Manual. Taking it as we’ve been taking it, it should read that “only one robot from an alliance may be in the opposing alliance’s zone at a time”. Taking it as written, it means one offense vs. up to 3 defense. Update #1 will hopefully address this. (If not, I expect both Q&A and Update #2 to get to this topic.)
I would assume that the zone does not start until after you pass through the tunnel (because that is the same line that would determine if you are in or out if you were to go over the bump). The bumps themselves are not considered part of either zone that they separate.
If I am RED, then only one opposing alliance robot (BLUE) is allowed in the opponent’s zone (RED, because the “opponent’s” statement refers back to the ‘opposing alliance’ earlier in the sentence, which is BLUE).
So, RED can only have one robot in the BLUE zone, BLUE can only have one robot in the RED zone.
Yeah, I agree. But if that was the intent of the rule, it should be rewritten without the “opposing” in it. It would make much more sense: “Only one alliance robot is allowed in the opponent’s zone.”