A bit more than poor sub-editing I'd say. It is just plain inconsistent. Even on the link you kindly attached it first says the travelcard covers:

"Bus services within the entire Greater London area (regardless of the zone the Travelcard actually covers)

Trams where your Travelcard includes Zone 3, 4, 5 or 6 "

which I read to mean that I can get on a bus in Zone 1 even if my travelcard doesn't cover that zone, and I can get on a tram in any zone as long as my card covers at least one of zones 3, 4, 5 and 6

but then later it says

"Points to note:

Your Travelcard must be valid for all the zones you travel through ...."


These statements are simply not consistent with each other. If tfl can't state the rules correctly, what chance does the man on the Clapham omnibus have!!