My big gripe (if you couldn't tell) is with repros. As for distributing patched roms, there are many reasons, including those beneficial to the end user, NOT to use pre-patched roms. That said, I've never asked anyone I saw distributing a pre-patched rom or ISO of one of my projects to stop. I mostly just make sure to provide patches with readmes as the official sources.
Repros on the other hand... As part of Dynamic Designs we've pursued sites selling repros of our work and requested they stop. They have complied temporarily at least. As for enforcement, I can't say that is a path I'd like to pursue vary far, but there's nothing wrong with making it clear to folks that they are using your work against your will, ESPECIALLY if money is involved.
I have yet to do this myself, but if I have an opportunity, I'll clearly license the next patch released outside of an "official" group under Creative Commons
so that my/our intentions regarding the work are more explicit. I also advocate for "fansub" style "Not for Sale or Rent", style disclaimers on splash screens which we at Dynamic Designs have done on several projects. This doesn't really address pre-patching, but I hope it helps a couple people buying or making repros stop and think.
If someone takes your or our illegal work and distributes it, do you/we really have a place to tell them not to distribute it?
Kinda, yeah. https://www.copyright.gov/help/faq/faq-general.html#protect