Do you have suggestions for organizing semi-dense apartment complexes such that there aren't more SSIDs than units and are there legal ways to safely share wifi

Do you have suggestions for organizing semi-dense apartment complexes such that there aren't more SSIDs than units and are there legal ways to safely share wifi with neighbors? It seems to me that most TOS agreements from ISPs seem to not like the idea that I might share my wifi with my neighbors... Also comments on 20 MHZ v 40 MHZ routers? For high latency, highly attenuated signal situations where varies from .1 Mbps to 3 Mbps, on OSX should one mess with MTU? Last unrelated tangent, how far are we until we can expect to start seeing widerspread municipal wifi deployments? Is it possible that school districts might expect to see 100% home internet penetration in a non-trivial percentage of American school district areas?