[Lil' Lavery]

That's pretty much what I'm saying. You need to be able to set up an alliance to avoid zone defense. In this year's game, there are 4 scoring "zones"; ramp-top, ramp-bottom, ranged, and corners. Having multiple bots in the same zone typically makes your alliance far easier to defend than having bots than can score in other areas. Just by merely adding "clutter" to that area, you can help a single bot play defense on an alliance partner if you are in that area. Thus why I also like play "interferance", especially when you're trying to stop a bot with more pushing power than yourself (instead of simply pushing your alliance partner, they'll push you into your alliance partner). If you are going to play "interferance", play it as far away from your alliance partner as possible.
By using multiple scoring areas, you force the defense to give-up any "double teams", highly reduce the possibility of them defending two robots with a single defender, and, at least during the defensive period, all but force them to allow one of your robots to score.
The only combination of scoring areas that might not do this, is ramp-top and ramp-bottom. Once both robots are set in position it will acheive the same effect, but because the ramp-top scoring bot has to pass through the ramp-bottom area to get into position, it does cause some situation where, at least for a few seconds, a single robot can defend multiple offensive bots.
Note also that it is the corner "zone", not the corner goal. A few robots do have the capability from scoring "outside" of the ramp, without being near the "starting zones". A vast majority of corner zone bots will be scoring in the corner goal though.

A well balanced alliance also needs at least 2 bots who can play defense, and play it well. Additionally, it needs at least one bot who can pick up off of the floor, and at least one who can receive from the human player. Preferably, they have two bots that can do both.