It will run on AMD processors, but be deliberately crippled. I remember reading a benchmark where by hacking the MKL lib and saying your AMD processor is some equivalend Intel one, gets you about 20% improved performance.
There was a lawsuit, but if it actually result in improved performance for non-Intel processors is unknown by me.
IIRC the lawsuit was about ICC (the compiler), not one of these libs. Could be wrong though.
No you're right, ICC would check to see if the CPU was "Intel Genuine" and if it was then you got highly optimized code with whatever extensions it could do. If it wasnt then you got generic assembly with no optimizations.