>>The captain on the day had to make the call: consider incurring a (IMVHO) miniscule added risk by taking time to dump fuel from the centre tank (leaving about 36 tonne undumpable) verses the possibly (who knows how big a...) risk of problems at the end of the rollout, following an overweight landing.<<
And some airlines make the decision for you. Air Canada has disabled fuel dump on their 767's to reduce maintenance costs.