I've flown a few SkyTeam RTW's in "C", only be aware then when only 2-class service available, they downgrade the C to Y instead of F, but if the plane has available F and you complain enough at the gate you generally will get F (and this happens on pd tickets as well!).
This standard is opposite of *A which upgrades C to F in 2-class.
[QUOTE=PMMMDL;8258436] WRT business class tickets and economy seating, that only applies to domestic USA flights where there is an extra $100 per leg surcharge to upgrade to domestic F. You will generally get business/first class on inter-european and inter-asian flights.