People appear to be mixing MEA (Minimum Enroute Altitude) up with MSA (meaning Minimum Safe Altitude, not Minimum Sector Altitude).
I think that's because the US has a rather more rigorous set of definitions for minimum altitudes, with MEAs, MRAs, MOCAs, MORAs etc. The "1000 ft above the highest obstacle within 5 nm" that comes from the UK's Rule 29 doesn't really have an equivalent label.