Since we were talking about entities "who do not self-identify as" resellers, who aren't resellers within the meaning of the term in the RAA, and who almost certainly don't carry out most of the functions of resellers set forth in Section 3.12 of the RAA, it's confusing at best to call all of these intermediaries "resellers."
I doubt that big resellers such as ISPs and hosting providers will turn into "gray market account holders." Domain name reselling is just an integrated part of their overall online offering. I don't expect that this type of reseller would register your domain in their own name (but I could be wrong, of course). I think this is much more common with your friendly neighborhood web developer, advertising/marketing agency, etc., who then registers the domain name with their registrar (often as if they were an end user). (I run across this quite often with smaller clients, and I try to fix it as quickly as possible.)
Greg S.