I acutally learned about this thread the other day from Interloc as he expressed his confusion about how anyone could think that snake had any spider in it. After looking at the photos he shared with me on facebook from this thread, my response to him was that I thought it very well could be the ugliest/most interesting spider I have ever seen.
I do think it is possible that it carries the spider gene. It could be really low expression, a paradox as mentioned by another member, or maybe the normal female actually did carry some sort of gene that messed up the spider expression. Who knows? I sure don't. Not unless I work with the snake in question or prove it out.
My first reaction: Very odd looking spider
My belief: Likely a spider
Am I 100% that it is a spider: Nope
Until we come up with a method for testing a snake's genetic makeup using DNA, we can't know what mutations are un a snake unless we breed them out. So to say that one person or another is 100% sure what genes an animal has based only on a picture isn't wise, in my humble opinion.