clay_c
In San Francisco, the streetcars are mapped as railway=tram, and the light rail is mapped as railway=light_rail. I see no issue here.

The light rail ("Muni Metro") in San Francisco is neither tram nor rail. It may have some street-running segments, but that alone does not make the Muni Metro a streetcar system. Any sort of railway can be embedded in a street (except perhaps railway=subway). This is the motivation behind using embedded=yes on railways—the fact that a segment of rail is embedded in a roadway is orthogonal to what kind of railway it is.

Are you suggesting that the entire Muni Metro system should be railway=tram? Or that certain segments should be railway=tram? Either of these would require a huge mechanical edit, as well as make San Francisco an exception to the guidelines used in the rest of North America.