Play on, T musicians -- the MBTA wisely decided to rachet down its proposed ban of amplified music on the subway platforms of Boston, after much outcry from riders, fans, and some famous buskers like Tracy Chapman and Mary Lou Lord. Of course, trumpets and "trumpet-like instruments" are now banned, and there are "designated areas" for players in the stations -- not including the primo spot in Davis Square where the excellent Rachel McCartney usually sets up. Meh.