Yeah, checks can be problematic like that. Here is how we solved it:
We process through WTS and EC. I was noticing more of sufer abuse, than affiliate abuse. Surfers were signing up WITH checks and info like email address:
asddfghjk
[email protected]
Now I think we all know this can't be a valid email address, Right? Well, I had to explain to the guys at another check processor that an email address cant have a space in it, nor is ".ccc" a properending. After about 5 minutes of arguing with her, she informed me that I was prolly wrong, and "this kind of thing happens". I then asked her to look up the name of that person signing up. Here is is:
adsf8d oi (or something to that effect)
Nice scrubbing you sons of bitches. I won the argument, switched the Check Processing, and now require a return email. Sales stayed about the same and I eliminated about 95% of the crap signups.