It would make a lot of sense to insta-ban anyone offering a giveaway. None of these things are kosher.
What things are you talking about?
Giveaways.
Why would you want to ban people for generously giving stuff away? Maybe an example would help here ...
You should know by now there is no generosity without hindsight on these boards. "Giveaways" have thus far primarily been used to spread pump-and-dump scamcoins, to acquire address lists of easily duped fools to mark them as viable targets for later scams or to establish false trust to get people to install trojans.
Here's the latest: https://bitcointalksearch.org/topic/beware-novacoin-phising-site-283953
Section rules + a sticky would stop that. A giveaway board would let people give away items/services instead of putting them in Marketplace.