The notion that 1 key must = 1 action (and not 1 keypress) means you could set up a G15 to send in /follow or /invite or /roll just like the WoW keyboard. In fact, the GM that said he uses the G11 pretty much validates that. He said you can create out of game macros as long as you can do the same thing in game and the keyboard macros act as extra macro slots.

EDIT:
Here is the quote, it's also in the wiki
"I use a G11 myself. Just don't use the macro keys to do anything a normal wow macro could not do in a single press. Think of them as extra storage for normal macros, and you're fine. "
Malkatorix, Blizzard Poster
http://forums.worldofwarcraft.com/th...=1&pageNo=2#27