Do you need a paid sub to view FMP Family Trees?

[kiterunner]

I don't mean the world tree type thing that they have on beta test, but individual trees built or uploaded by members. I have a tree on FMP - if I invite someone to view it, do they (or do I) need a paid sub for them to be able to view it, anyone know? The FAQ's only say they need to have an FMP account.