Proposer withholding and collation availability traps

That seems much stronger. Difficult to see this scheme being attacked. The only way I could see it is if the proposer bribed the validator to withhold the data they have. I don’t see that as being very likely because once an attacker has paid him, the validator can do what he likes with the data… unless the proposer gave the validator 99% of the data but could use the 1% to slash the validator’s balance.