Another thing to keep in mind is that - even legally - this is all opinion and conjecture.
Modern software comes with a license agreement and is generally (but not universally) accepted that you can make a single copy of the software for archival purposes.
Arcade games were originally sold as a complete item, and you owned the cabinet, the electronics, and the manual, if it included one. There was no mention of licensing, you owned the game. There was also no mention of whether you could or could not dump the ROMS and then whether you could or could not distribute them after you dumped them. (Primarily because, at the time, the machines to dump them cost many times more than the games themselves, so nobody would seriously consider this).
Basically - ownership and distribution of any roms except the three that are released as public domain on MAME.net (Robby-Roto and a couple of others), is a legal gray area (including IMHO StarRoms and the Capcom Roms that ship with the HotRod) and will remain so until the issue is challenged in court and decided by a judge (and even then there is a possibility of the decision being overturned on appeal).
However, everyone (well, most everyone) here, would prefer for it to remain a gray issue so we can deny that we are knowingly breaking any laws, so there is a general policy of "Don't ask, Don't tell", NTTIAWWT.
