Some Rom sites get closed. Reselling is generally always frowned upon, especially when done commercially, where its prosecutable (inot very different from bootleg commerce).
At the level of individual users, ISPs can throthle connections, send notices about unlawful downloads, and similar. It rarely goes further than similar 'trouble', at the personal non-commercial non-redistributing level.
Other than that, emulators are pretty much safe, and created/published by the book, avoiding liabilities.