Safety date is a person that accompanies you to friend's or family event, in order to a) give the appearance that you are seeing people and not isolated from society, b) avoid being set up on blind dates by well meaning friends.
Safety date（暂译为"临时伴侣"）就是去参加朋友或家庭聚会的时候临时带去的男/女伴，这样做的原因有二：一是为了让人们看到你并没有让自己与世隔绝，还是在跟人交往的；二是为了杜绝朋友们善意安排的相亲的活动。
For example:
Jack brought a safety date to his aunt's dinner party. He did this because his aunt considered herself an "accomplished match maker."
杰克带了个临时伴侣去参加她姨妈的聚餐。他这样做是因为他姨妈一直自诩为"成功的红娘"。
