Hmm, a spammer used something like that in my forum. I reported them to cj and godaddy, but unfortunately, they got their clicks and dissapeared.
Seems that if someone clicks your affiliate link you get the credit. If you post your affiliate link in some one elses forum, expect them to change it to their own id.
To have a redirect and then spam someone is a sure way to get blacklisted. I always log things now. If I see a redirect in my forum, I "freeze it" get the affiliate id, and report to the affiliate provider, who then in turn freezes all revenue.
If your affiliate ID is on your own hosted webpage, how is someone going to change your html to get the credit? Do tell me, as I need to know this, as anyone else would.
I have been assured by cj and godaddy, that if they click from your page, you get credit, and that these big players have sophisticated tracking, where they even track machine access codes.
So why again must you cloak your affiliate id?
Funny thing is I ran accross a script earlier today that was free and would do what you ask. I think it was on pagerank10.co.uk in their forum posted by a spammer LOL