There's so much here, I hardly know where to start. First, in my opinion, if an amplifier can oscillate just because of using a certain brand of speaker cable, either the amp, or the cables, or both, are poorly designed. Second, oscillation is a signal coming out with no signal going in. Oscillation occurs in an amp when specific conditions are met regarding the resistance, capacitance, and inductance values connected to the amps input or output. The analogy to the bridge is a good one, or think of holding a mike next to a speaker in a PA system- you get a howl or a whistle. An amp that oscillates because of the speaker connections will put out a signal even if the inputs are disconnected; this is usually called singing (it's like a dog whistle at high volumes.) The amp will have a bright, edgy sound, because of all the distortion caused by the oscillation signals, and the output transistors will get very hot. In a really bad case (think dog whistle at 100 watts), all this happens in a few seconds, and then you get silence, because the guts of the transistors are now little melted balls of metal. (The next sound is usually the owner crying.) This situation just shouldn't be able to happen with changing cables. Last, I have a lot of respect for Pass, and what he says is true, but irrelevant. The cables are too short, and frequencies are too low, for there to be a significant reflection. Reflections are a problem when the cables's amplifier end is at one voltage, while the speaker end is at another (the amp is already putting out note B while note A is just getting to the speaker.) Don't worry about it until your speaker cables are over a half mile long. My apologies for the long post.
