Let's keep this one on the up and up and no name calling. Here's the premise on bi-amping:
200W + 200W = 400W
200W + 200W = 200W (Okay, maybe a bit more around the crossover)
Reasoning: Both Amps are generating full range signal but pushing seperate "halfs" of a speaker. If you are trying to generate a loud 80Hz signal, how much power can you push to it? Only 200W... Virtually any signal can only have 200W directed to it. Same as if you only had one amp...
Lets say that a signal causes a clip due to the extreme bass on the amp driving the woofer section, what happens up top? The top amp is till trying to produce the full range signal but pushing it into a brick wall (AKA Crossover) I'm guessing that the clipping signal is still present and you will blow your tweeter. This one is the more confusing since the amp is seeing an infinate resistance leading to 0 amps on the circuit... This is the piece I'm missing.
At this point, the only purpose to bi-amping that I see is that you can tailer amps to the specific strengths.
Add an external X-over before the amps and it's a totally different ballgame. Then you could put a 5W SET on the top and 500W down below and have great results.
Let the debate begin, and remember, we're all freinds here and keep thinking in dynamic power...