This just makes no sense.
Data is data, data can be anything, data can be illegal, data can even BECOME illegal after years.
Datacoin is a blockchain, you can't change the blockchain after a block is inserted without changing the whole chain, period.
You can't enforce the data type to store in the blockchain, there could be a consensus like in the envelope protocol but that is just a
consensus, not a mandatory rule.
I would ask the people that is so worried about illegal content to go ask a lawyer instead of posting their worries here, or at least before posting.

Pleas read the reddit thread some posts above this for some nice arguments about posting illegal content to a blockchain (any blockchain).