Do AF or KL have similar waivers? Maybe you can refer the DL agent to their partners' warnings and go from there?

And what i really meant to ask is... what is this FRA turning into CDG now? Crazy!

If all else fails and you do get delayed and miss the train, buy a ticket and submit to DL for reimbursement. They may take pity on you (though if the delay is not their doing, they might not have to).