A reply Major Nelson received from Freeverse (developer): "We have been made aware that some gamers are experiencing discomfort with continued play of the recently released Xbox LIVE Arcade game Marathon Durandal. Within the next few days we will implement a dash message on the download screen to advise users on steps they can take if this affects them and are investigating other options to address the issue."
Frankly, if Microsoft is worried enough to implement some warning/notification/disclaimer via the dash, if I felt sick I would stop playing it until it gets resolved. Thanks to John at Gamerscoreblog and Major Nelson for the heads up.