anyone who's taken a city bus (in the states) is familiar with this sign posted above the seats directly behind the bus driver: "these seats must be vacated for seniors and disabled persons when needed." if disability is sometimes hard to gauge by simply looking at someone, seniority is much harder--what might appear to me, a fabulous older woman, might be senior citizen to someone else. worse yet? offering one of these seats to a pregnant woman (as a matter of courtesy), only to be told, "i'm not pregnant, sweetie." what to do!