I haven't seen this charge for spikes yet. It would seam to me that a no cost option for either rubber feet or spikes would be more appropriate. And if a person wanted to order a set of 'premium' fancy spikes, they would come with an additional charge.
I do know that Axiom is working on the whole customization program to offer customers a slew of different options. This may just be one more step in that process.
I have hard wood floors all over the place so I hate it when stuff comes with spikes. They usually send you little pads to go under them, but they sure are a pain in the rear. Just try balancing a 70 pound speaker with spiked feet while trying to position them over the pads once.... which is something I have to do today. Oh joy, oh joy..