http://musicbrainz.org/ws/2/recording/99244237-850b-4a93-904d-57305bcadb4e?inc=aliases+artist-credits+releases+artist-rels&fmt=json has

aliases: [ ]

for Trent Reznor, who actually has an alias. I assume these just aren't loaded here at all - the XML WS explicitly blocks displaying aliases in this case. We should probably do the same in the JSON one.