I never suggested that they would sue fans... that would be pointless. Rather, I think they are going to use fans as a weapon against independent developers, and that these developers should sue both them and Steam before it's too late.
Companies know that high tech sells better than low tech; it also fits in with the "big tent" company style that megacorps subscribe to (Westerners are unaware that unions are still strong in Japan, and that the courts side with them enough that to get rich there you have to go big or go bust). The proliferation of low tech, very cheap games is presenting a dilemma as the big publishers are slowly dying from a thousand cuts. Talk to a factory worker and you'll realize few of them are willing to buy a game anymore without cutting edge graphics... these soft core gamers are a big market now, bigger even than the movie industry, and everyone wants a piece of the pie. Hard core gamers play both these games and lighter, more traditional games (and a segment play RPGs). The question of how to retain share of these smaller market segments has been bedeviling publishers for some time; as we've seen, Nintendo is suffering seriously from competition with license-free competitors operating from Steam and Google Play. The market is getting swamped with decently drawn 2D games thanks to the development of easy to use tools which reduce content creator reliance on career programmers (if you want to see these, check out indieDB). The question has been how to repress this growing freedom and self-assertion among the creative classes (which is likely to result in stronger, more diverse competition and more upward wage pressure for in-house developers) while optimally monetizing the consumer. This appears to be their answer: to create a juxtaposition of profit-seeking content creators against non-profit seeking creators (leading fans) while monetizing the latter all through sustained psychological gambit (community management, appeal to nostalgia, and brute force advertising/endorsement).
In other words, companies are paying attention to what's being done here and at other fan game sites, and they want to take it to a high enough level that it eclipses everything. Killing two birds with one stone.
Hopefully it dies within the first couple months. People will balk at the creative straighjacket of 64 colors and 2 operator FM sound. If they do enhance the emulator beyond this, then it will still beggar belief why people don't just grab something off of indieDB and go nuts making something that might allow them to quit their day job and even garner them a measure of fame. A triumph of advertising over common sense that will doubt bring about an deeper level of cynicism of the American consumer.