The new swiping-mode of the sentence-collector makes the review process much quicker and it would filter out the worst sentences. I would be willing to review maybe 10 000 sentences in German. (I already reviewed that much for the Esperanto sentence collection) We would need at least another 19 people doing the same to import the complete dataset for one language. Likely more since sentences need more than two votes when people disagree.
That being said I recommend everyone to download the dataset and search for some words, topics and phrases that come to your mind that could be problematic. As far as I can see it there are very few really problematic sentences.
In the Europarl dataset most controversial opinions are part of a longer sentence like: “Mister President I have to say that …” and this puts the opinion in a context that makes it easier to be read by someone who doesn’t like it. But there will be some people who will complain about some sentences since they are all highly political. But I could live with that.