How similar is similar, #2

Two more magazines sharing the same name. The magazine on the left is the long-standing UK architecture & design title, launched way back in 1983. And on the right is the brand new launch from US media magnate Martha Stewart.

The original Blueprint is a specialist trade magazine, the new Blueprint a consumer lifestyle title. And yes the covers don't look much alike. But it's that same-name thing again - how can two magazines, however different, share the same name? I've known plenty of projected launches have working titles rejected because the name is already in use by another magazine. How does Martha Stewart get away with this?

(Thanks to Marcus Piper)